17dd78cd84c33809f002f43d96363b3d4c61d6b9
[exim.git] / src / src / smtp_in.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for handling an incoming SMTP call. */
9
10
11 #include "exim.h"
12 #include <assert.h>
13
14
15 /* Initialize for TCP wrappers if so configured. It appears that the macro
16 HAVE_IPV6 is used in some versions of the tcpd.h header, so we unset it before
17 including that header, and restore its value afterwards. */
18
19 #ifdef USE_TCP_WRAPPERS
20
21 #if HAVE_IPV6
22 #define EXIM_HAVE_IPV6
23 #endif
24 #undef HAVE_IPV6
25 #include <tcpd.h>
26 #undef HAVE_IPV6
27 #ifdef EXIM_HAVE_IPV6
28 #define HAVE_IPV6 TRUE
29 #endif
30
31 int allow_severity = LOG_INFO;
32 int deny_severity = LOG_NOTICE;
33 uschar *tcp_wrappers_name;
34 #endif
35
36
37 /* Size of buffer for reading SMTP commands. We used to use 512, as defined
38 by RFC 821. However, RFC 1869 specifies that this must be increased for SMTP
39 commands that accept arguments, and this in particular applies to AUTH, where
40 the data can be quite long. More recently this value was 2048 in Exim;
41 however, RFC 4954 (circa 2007) recommends 12288 bytes to handle AUTH. Clients
42 such as Thunderbird will send an AUTH with an initial-response for GSSAPI.
43 The maximum size of a Kerberos ticket under Windows 2003 is 12000 bytes, and
44 we need room to handle large base64-encoded AUTHs for GSSAPI.
45 */
46
47 #define smtp_cmd_buffer_size 16384
48
49 /* Size of buffer for reading SMTP incoming packets */
50
51 #define in_buffer_size 8192
52
53 /* Structure for SMTP command list */
54
55 typedef struct {
56 const char *name;
57 int len;
58 short int cmd;
59 short int has_arg;
60 short int is_mail_cmd;
61 } smtp_cmd_list;
62
63 /* Codes for identifying commands. We order them so that those that come first
64 are those for which synchronization is always required. Checking this can help
65 block some spam. */
66
67 enum {
68 /* These commands are required to be synchronized, i.e. to be the last in a
69 block of commands when pipelining. */
70
71 HELO_CMD, EHLO_CMD, DATA_CMD, /* These are listed in the pipelining */
72 VRFY_CMD, EXPN_CMD, NOOP_CMD, /* RFC as requiring synchronization */
73 ETRN_CMD, /* This by analogy with TURN from the RFC */
74 STARTTLS_CMD, /* Required by the STARTTLS RFC */
75 TLS_AUTH_CMD, /* auto-command at start of SSL */
76
77 /* This is a dummy to identify the non-sync commands when pipelining */
78
79 NON_SYNC_CMD_PIPELINING,
80
81 /* These commands need not be synchronized when pipelining */
82
83 MAIL_CMD, RCPT_CMD, RSET_CMD,
84
85 /* RFC3030 section 2: "After all MAIL and RCPT responses are collected and
86 processed the message is sent using a series of BDAT commands"
87 implies that BDAT should be synchronized. However, we see Google, at least,
88 sending MAIL,RCPT,BDAT-LAST in a single packet, clearly not waiting for
89 processing of the RPCT response(s). We shall do the same, and not require
90 synch for BDAT. */
91
92 BDAT_CMD,
93
94 /* This is a dummy to identify the non-sync commands when not pipelining */
95
96 NON_SYNC_CMD_NON_PIPELINING,
97
98 /* I have been unable to find a statement about the use of pipelining
99 with AUTH, so to be on the safe side it is here, though I kind of feel
100 it should be up there with the synchronized commands. */
101
102 AUTH_CMD,
103
104 /* I'm not sure about these, but I don't think they matter. */
105
106 QUIT_CMD, HELP_CMD,
107
108 #ifdef SUPPORT_PROXY
109 PROXY_FAIL_IGNORE_CMD,
110 #endif
111
112 /* These are specials that don't correspond to actual commands */
113
114 EOF_CMD, OTHER_CMD, BADARG_CMD, BADCHAR_CMD, BADSYN_CMD,
115 TOO_MANY_NONMAIL_CMD };
116
117
118 /* This is a convenience macro for adding the identity of an SMTP command
119 to the circular buffer that holds a list of the last n received. */
120
121 #define HAD(n) \
122 smtp_connection_had[smtp_ch_index++] = n; \
123 if (smtp_ch_index >= SMTP_HBUFF_SIZE) smtp_ch_index = 0
124
125
126 /*************************************************
127 * Local static variables *
128 *************************************************/
129
130 static auth_instance *authenticated_by;
131 static BOOL auth_advertised;
132 #ifdef SUPPORT_TLS
133 static BOOL tls_advertised;
134 #endif
135 static BOOL dsn_advertised;
136 static BOOL esmtp;
137 static BOOL helo_required = FALSE;
138 static BOOL helo_verify = FALSE;
139 static BOOL helo_seen;
140 static BOOL helo_accept_junk;
141 static BOOL count_nonmail;
142 static BOOL pipelining_advertised;
143 static BOOL rcpt_smtp_response_same;
144 static BOOL rcpt_in_progress;
145 static int nonmail_command_count;
146 static BOOL smtp_exit_function_called = 0;
147 #ifdef SUPPORT_I18N
148 static BOOL smtputf8_advertised;
149 #endif
150 static int synprot_error_count;
151 static int unknown_command_count;
152 static int sync_cmd_limit;
153 static int smtp_write_error = 0;
154
155 static uschar *rcpt_smtp_response;
156 static uschar *smtp_data_buffer;
157 static uschar *smtp_cmd_data;
158
159 /* We need to know the position of RSET, HELO, EHLO, AUTH, and STARTTLS. Their
160 final fields of all except AUTH are forced TRUE at the start of a new message
161 setup, to allow one of each between messages that is not counted as a nonmail
162 command. (In fact, only one of HELO/EHLO is not counted.) Also, we have to
163 allow a new EHLO after starting up TLS.
164
165 AUTH is "falsely" labelled as a mail command initially, so that it doesn't get
166 counted. However, the flag is changed when AUTH is received, so that multiple
167 failing AUTHs will eventually hit the limit. After a successful AUTH, another
168 AUTH is already forbidden. After a TLS session is started, AUTH's flag is again
169 forced TRUE, to allow for the re-authentication that can happen at that point.
170
171 QUIT is also "falsely" labelled as a mail command so that it doesn't up the
172 count of non-mail commands and possibly provoke an error.
173
174 tls_auth is a pseudo-command, never expected in input. It is activated
175 on TLS startup and looks for a tls authenticator. */
176
177 static smtp_cmd_list cmd_list[] = {
178 /* name len cmd has_arg is_mail_cmd */
179
180 { "rset", sizeof("rset")-1, RSET_CMD, FALSE, FALSE }, /* First */
181 { "helo", sizeof("helo")-1, HELO_CMD, TRUE, FALSE },
182 { "ehlo", sizeof("ehlo")-1, EHLO_CMD, TRUE, FALSE },
183 { "auth", sizeof("auth")-1, AUTH_CMD, TRUE, TRUE },
184 #ifdef SUPPORT_TLS
185 { "starttls", sizeof("starttls")-1, STARTTLS_CMD, FALSE, FALSE },
186 { "tls_auth", 0, TLS_AUTH_CMD, FALSE, TRUE },
187 #endif
188
189 /* If you change anything above here, also fix the definitions below. */
190
191 { "mail from:", sizeof("mail from:")-1, MAIL_CMD, TRUE, TRUE },
192 { "rcpt to:", sizeof("rcpt to:")-1, RCPT_CMD, TRUE, TRUE },
193 { "data", sizeof("data")-1, DATA_CMD, FALSE, TRUE },
194 { "bdat", sizeof("bdat")-1, BDAT_CMD, TRUE, TRUE },
195 { "quit", sizeof("quit")-1, QUIT_CMD, FALSE, TRUE },
196 { "noop", sizeof("noop")-1, NOOP_CMD, TRUE, FALSE },
197 { "etrn", sizeof("etrn")-1, ETRN_CMD, TRUE, FALSE },
198 { "vrfy", sizeof("vrfy")-1, VRFY_CMD, TRUE, FALSE },
199 { "expn", sizeof("expn")-1, EXPN_CMD, TRUE, FALSE },
200 { "help", sizeof("help")-1, HELP_CMD, TRUE, FALSE }
201 };
202
203 static smtp_cmd_list *cmd_list_end =
204 cmd_list + sizeof(cmd_list)/sizeof(smtp_cmd_list);
205
206 #define CMD_LIST_RSET 0
207 #define CMD_LIST_HELO 1
208 #define CMD_LIST_EHLO 2
209 #define CMD_LIST_AUTH 3
210 #define CMD_LIST_STARTTLS 4
211 #define CMD_LIST_TLS_AUTH 5
212
213 /* This list of names is used for performing the smtp_no_mail logging action.
214 It must be kept in step with the SCH_xxx enumerations. */
215
216 static uschar *smtp_names[] =
217 {
218 US"NONE", US"AUTH", US"DATA", US"BDAT", US"EHLO", US"ETRN", US"EXPN",
219 US"HELO", US"HELP", US"MAIL", US"NOOP", US"QUIT", US"RCPT", US"RSET",
220 US"STARTTLS", US"VRFY" };
221
222 static uschar *protocols_local[] = {
223 US"local-smtp", /* HELO */
224 US"local-smtps", /* The rare case EHLO->STARTTLS->HELO */
225 US"local-esmtp", /* EHLO */
226 US"local-esmtps", /* EHLO->STARTTLS->EHLO */
227 US"local-esmtpa", /* EHLO->AUTH */
228 US"local-esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
229 };
230 static uschar *protocols[] = {
231 US"smtp", /* HELO */
232 US"smtps", /* The rare case EHLO->STARTTLS->HELO */
233 US"esmtp", /* EHLO */
234 US"esmtps", /* EHLO->STARTTLS->EHLO */
235 US"esmtpa", /* EHLO->AUTH */
236 US"esmtpsa" /* EHLO->STARTTLS->EHLO->AUTH */
237 };
238
239 #define pnormal 0
240 #define pextend 2
241 #define pcrpted 1 /* added to pextend or pnormal */
242 #define pauthed 2 /* added to pextend */
243
244 /* Sanity check and validate optional args to MAIL FROM: envelope */
245 enum {
246 ENV_MAIL_OPT_NULL,
247 ENV_MAIL_OPT_SIZE, ENV_MAIL_OPT_BODY, ENV_MAIL_OPT_AUTH,
248 #ifndef DISABLE_PRDR
249 ENV_MAIL_OPT_PRDR,
250 #endif
251 ENV_MAIL_OPT_RET, ENV_MAIL_OPT_ENVID,
252 #ifdef SUPPORT_I18N
253 ENV_MAIL_OPT_UTF8,
254 #endif
255 };
256 typedef struct {
257 uschar * name; /* option requested during MAIL cmd */
258 int value; /* enum type */
259 BOOL need_value; /* TRUE requires value (name=value pair format)
260 FALSE is a singleton */
261 } env_mail_type_t;
262 static env_mail_type_t env_mail_type_list[] = {
263 { US"SIZE", ENV_MAIL_OPT_SIZE, TRUE },
264 { US"BODY", ENV_MAIL_OPT_BODY, TRUE },
265 { US"AUTH", ENV_MAIL_OPT_AUTH, TRUE },
266 #ifndef DISABLE_PRDR
267 { US"PRDR", ENV_MAIL_OPT_PRDR, FALSE },
268 #endif
269 { US"RET", ENV_MAIL_OPT_RET, TRUE },
270 { US"ENVID", ENV_MAIL_OPT_ENVID, TRUE },
271 #ifdef SUPPORT_I18N
272 { US"SMTPUTF8",ENV_MAIL_OPT_UTF8, FALSE }, /* rfc6531 */
273 #endif
274 /* keep this the last entry */
275 { US"NULL", ENV_MAIL_OPT_NULL, FALSE },
276 };
277
278 /* When reading SMTP from a remote host, we have to use our own versions of the
279 C input-reading functions, in order to be able to flush the SMTP output only
280 when about to read more data from the socket. This is the only way to get
281 optimal performance when the client is using pipelining. Flushing for every
282 command causes a separate packet and reply packet each time; saving all the
283 responses up (when pipelining) combines them into one packet and one response.
284
285 For simplicity, these functions are used for *all* SMTP input, not only when
286 receiving over a socket. However, after setting up a secure socket (SSL), input
287 is read via the OpenSSL library, and another set of functions is used instead
288 (see tls.c).
289
290 These functions are set in the receive_getc etc. variables and called with the
291 same interface as the C functions. However, since there can only ever be
292 one incoming SMTP call, we just use a single buffer and flags. There is no need
293 to implement a complicated private FILE-like structure.*/
294
295 static uschar *smtp_inbuffer;
296 static uschar *smtp_inptr;
297 static uschar *smtp_inend;
298 static int smtp_had_eof;
299 static int smtp_had_error;
300
301
302 /* forward declarations */
303 int bdat_ungetc(int ch);
304 static int smtp_read_command(BOOL check_sync);
305 static int synprot_error(int type, int code, uschar *data, uschar *errmess);
306 static void smtp_quit_handler(uschar **, uschar **);
307 static void smtp_rset_handler(void);
308
309 /*************************************************
310 * SMTP version of getc() *
311 *************************************************/
312
313 /* This gets the next byte from the SMTP input buffer. If the buffer is empty,
314 it flushes the output, and refills the buffer, with a timeout. The signal
315 handler is set appropriately by the calling function. This function is not used
316 after a connection has negotated itself into an TLS/SSL state.
317
318 Arguments: none
319 Returns: the next character or EOF
320 */
321
322 int
323 smtp_getc(void)
324 {
325 if (smtp_inptr >= smtp_inend)
326 {
327 int rc, save_errno;
328 if (!smtp_out) return EOF;
329 fflush(smtp_out);
330 if (smtp_receive_timeout > 0) alarm(smtp_receive_timeout);
331 rc = read(fileno(smtp_in), smtp_inbuffer, in_buffer_size);
332 save_errno = errno;
333 alarm(0);
334 if (rc <= 0)
335 {
336 /* Must put the error text in fixed store, because this might be during
337 header reading, where it releases unused store above the header. */
338 if (rc < 0)
339 {
340 smtp_had_error = save_errno;
341 smtp_read_error = string_copy_malloc(
342 string_sprintf(" (error: %s)", strerror(save_errno)));
343 }
344 else smtp_had_eof = 1;
345 return EOF;
346 }
347 #ifndef DISABLE_DKIM
348 dkim_exim_verify_feed(smtp_inbuffer, rc);
349 #endif
350 smtp_inend = smtp_inbuffer + rc;
351 smtp_inptr = smtp_inbuffer;
352 }
353 return *smtp_inptr++;
354 }
355
356 void
357 smtp_get_cache(void)
358 {
359 #ifndef DISABLE_DKIM
360 int n = smtp_inend - smtp_inptr;
361 if (n > 0)
362 dkim_exim_verify_feed(smtp_inptr, n);
363 #endif
364 }
365
366
367 /* Get a byte from the smtp input, in CHUNKING mode. Handle ack of the
368 previous BDAT chunk and getting new ones when we run out. Uses the
369 underlying smtp_getc or tls_getc both for that and for getting the
370 (buffered) data byte. EOD signals (an expected) no further data.
371 ERR signals a protocol error, and EOF a closed input stream.
372
373 Called from read_bdat_smtp() in receive.c for the message body, but also
374 by the headers read loop in receive_msg(); manipulates chunking_state
375 to handle the BDAT command/response.
376 Placed here due to the correlation with the above smtp_getc(), which it wraps,
377 and also by the need to do smtp command/response handling.
378
379 Arguments: none
380 Returns: the next character or ERR, EOD or EOF
381 */
382
383 int
384 bdat_getc(void)
385 {
386 uschar * user_msg = NULL;
387 uschar * log_msg;
388
389 for(;;)
390 {
391 if (chunking_data_left-- > 0)
392 return lwr_receive_getc();
393
394 receive_getc = lwr_receive_getc;
395 receive_ungetc = lwr_receive_ungetc;
396
397 /* If not the last, ack the received chunk. The last response is delayed
398 until after the data ACL decides on it */
399
400 if (chunking_state == CHUNKING_LAST)
401 {
402 #ifndef DISABLE_DKIM
403 dkim_exim_verify_feed(NULL, 0); /* notify EOD */
404 #endif
405 return EOD;
406 }
407
408 chunking_state = CHUNKING_OFFERED;
409 smtp_printf("250 %u byte chunk received\r\n", chunking_datasize);
410
411 /* Expect another BDAT cmd from input. RFC 3030 says nothing about
412 QUIT, RSET or NOOP but handling them seems obvious */
413
414 next_cmd:
415 switch(smtp_read_command(TRUE))
416 {
417 default:
418 (void) synprot_error(L_smtp_protocol_error, 503, NULL,
419 US"only BDAT permissible after non-LAST BDAT");
420
421 repeat_until_rset:
422 switch(smtp_read_command(TRUE))
423 {
424 case QUIT_CMD: smtp_quit_handler(&user_msg, &log_msg); /*FALLTHROUGH */
425 case EOF_CMD: return EOF;
426 case RSET_CMD: smtp_rset_handler(); return ERR;
427 default: if (synprot_error(L_smtp_protocol_error, 503, NULL,
428 US"only RSET accepted now") > 0)
429 return EOF;
430 goto repeat_until_rset;
431 }
432
433 case QUIT_CMD:
434 smtp_quit_handler(&user_msg, &log_msg);
435 /*FALLTHROUGH*/
436 case EOF_CMD:
437 return EOF;
438
439 case RSET_CMD:
440 smtp_rset_handler();
441 return ERR;
442
443 case NOOP_CMD:
444 HAD(SCH_NOOP);
445 smtp_printf("250 OK\r\n");
446 goto next_cmd;
447
448 case BDAT_CMD:
449 {
450 int n;
451
452 if (sscanf(CS smtp_cmd_data, "%u %n", &chunking_datasize, &n) < 1)
453 {
454 (void) synprot_error(L_smtp_protocol_error, 501, NULL,
455 US"missing size for BDAT command");
456 return ERR;
457 }
458 chunking_state = strcmpic(smtp_cmd_data+n, US"LAST") == 0
459 ? CHUNKING_LAST : CHUNKING_ACTIVE;
460 chunking_data_left = chunking_datasize;
461
462 if (chunking_datasize == 0)
463 if (chunking_state == CHUNKING_LAST)
464 return EOD;
465 else
466 {
467 (void) synprot_error(L_smtp_protocol_error, 504, NULL,
468 US"zero size for BDAT command");
469 goto repeat_until_rset;
470 }
471
472 receive_getc = bdat_getc;
473 receive_ungetc = bdat_ungetc;
474 break; /* to top of main loop */
475 }
476 }
477 }
478 }
479
480 static void
481 bdat_flush_data(void)
482 {
483 while (chunking_data_left-- > 0)
484 if (lwr_receive_getc() < 0)
485 break;
486
487 receive_getc = lwr_receive_getc;
488 receive_ungetc = lwr_receive_ungetc;
489
490 if (chunking_state != CHUNKING_LAST)
491 chunking_state = CHUNKING_OFFERED;
492 }
493
494
495
496
497 /*************************************************
498 * SMTP version of ungetc() *
499 *************************************************/
500
501 /* Puts a character back in the input buffer. Only ever
502 called once.
503
504 Arguments:
505 ch the character
506
507 Returns: the character
508 */
509
510 int
511 smtp_ungetc(int ch)
512 {
513 *--smtp_inptr = ch;
514 return ch;
515 }
516
517
518 int
519 bdat_ungetc(int ch)
520 {
521 chunking_data_left++;
522 return lwr_receive_ungetc(ch);
523 }
524
525
526
527 /*************************************************
528 * SMTP version of feof() *
529 *************************************************/
530
531 /* Tests for a previous EOF
532
533 Arguments: none
534 Returns: non-zero if the eof flag is set
535 */
536
537 int
538 smtp_feof(void)
539 {
540 return smtp_had_eof;
541 }
542
543
544
545
546 /*************************************************
547 * SMTP version of ferror() *
548 *************************************************/
549
550 /* Tests for a previous read error, and returns with errno
551 restored to what it was when the error was detected.
552
553 Arguments: none
554 Returns: non-zero if the error flag is set
555 */
556
557 int
558 smtp_ferror(void)
559 {
560 errno = smtp_had_error;
561 return smtp_had_error;
562 }
563
564
565
566 /*************************************************
567 * Test for characters in the SMTP buffer *
568 *************************************************/
569
570 /* Used at the end of a message
571
572 Arguments: none
573 Returns: TRUE/FALSE
574 */
575
576 BOOL
577 smtp_buffered(void)
578 {
579 return smtp_inptr < smtp_inend;
580 }
581
582
583
584 /*************************************************
585 * Write formatted string to SMTP channel *
586 *************************************************/
587
588 /* This is a separate function so that we don't have to repeat everything for
589 TLS support or debugging. It is global so that the daemon and the
590 authentication functions can use it. It does not return any error indication,
591 because major problems such as dropped connections won't show up till an output
592 flush for non-TLS connections. The smtp_fflush() function is available for
593 checking that: for convenience, TLS output errors are remembered here so that
594 they are also picked up later by smtp_fflush().
595
596 Arguments:
597 format format string
598 ... optional arguments
599
600 Returns: nothing
601 */
602
603 void
604 smtp_printf(const char *format, ...)
605 {
606 va_list ap;
607
608 va_start(ap, format);
609 smtp_vprintf(format, ap);
610 va_end(ap);
611 }
612
613 /* This is split off so that verify.c:respond_printf() can, in effect, call
614 smtp_printf(), bearing in mind that in C a vararg function can't directly
615 call another vararg function, only a function which accepts a va_list. */
616
617 void
618 smtp_vprintf(const char *format, va_list ap)
619 {
620 BOOL yield;
621
622 yield = string_vformat(big_buffer, big_buffer_size, format, ap);
623
624 DEBUG(D_receive)
625 {
626 void *reset_point = store_get(0);
627 uschar *msg_copy, *cr, *end;
628 msg_copy = string_copy(big_buffer);
629 end = msg_copy + Ustrlen(msg_copy);
630 while ((cr = Ustrchr(msg_copy, '\r')) != NULL) /* lose CRs */
631 memmove(cr, cr + 1, (end--) - cr);
632 debug_printf("SMTP>> %s", msg_copy);
633 store_reset(reset_point);
634 }
635
636 if (!yield)
637 {
638 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_printf()");
639 smtp_closedown(US"Unexpected error");
640 exim_exit(EXIT_FAILURE);
641 }
642
643 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
644 have had the same. Note: this code is also present in smtp_respond(). It would
645 be tidier to have it only in one place, but when it was added, it was easier to
646 do it that way, so as not to have to mess with the code for the RCPT command,
647 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
648
649 if (rcpt_in_progress)
650 {
651 if (rcpt_smtp_response == NULL)
652 rcpt_smtp_response = string_copy(big_buffer);
653 else if (rcpt_smtp_response_same &&
654 Ustrcmp(rcpt_smtp_response, big_buffer) != 0)
655 rcpt_smtp_response_same = FALSE;
656 rcpt_in_progress = FALSE;
657 }
658
659 /* Now write the string */
660
661 #ifdef SUPPORT_TLS
662 if (tls_in.active >= 0)
663 {
664 if (tls_write(TRUE, big_buffer, Ustrlen(big_buffer)) < 0)
665 smtp_write_error = -1;
666 }
667 else
668 #endif
669
670 if (fprintf(smtp_out, "%s", big_buffer) < 0) smtp_write_error = -1;
671 }
672
673
674
675 /*************************************************
676 * Flush SMTP out and check for error *
677 *************************************************/
678
679 /* This function isn't currently used within Exim (it detects errors when it
680 tries to read the next SMTP input), but is available for use in local_scan().
681 For non-TLS connections, it flushes the output and checks for errors. For
682 TLS-connections, it checks for a previously-detected TLS write error.
683
684 Arguments: none
685 Returns: 0 for no error; -1 after an error
686 */
687
688 int
689 smtp_fflush(void)
690 {
691 if (tls_in.active < 0 && fflush(smtp_out) != 0) smtp_write_error = -1;
692 return smtp_write_error;
693 }
694
695
696
697 /*************************************************
698 * SMTP command read timeout *
699 *************************************************/
700
701 /* Signal handler for timing out incoming SMTP commands. This attempts to
702 finish off tidily.
703
704 Argument: signal number (SIGALRM)
705 Returns: nothing
706 */
707
708 static void
709 command_timeout_handler(int sig)
710 {
711 sig = sig; /* Keep picky compilers happy */
712 log_write(L_lost_incoming_connection,
713 LOG_MAIN, "SMTP command timeout on%s connection from %s",
714 (tls_in.active >= 0)? " TLS" : "",
715 host_and_ident(FALSE));
716 if (smtp_batched_input)
717 moan_smtp_batch(NULL, "421 SMTP command timeout"); /* Does not return */
718 smtp_notquit_exit(US"command-timeout", US"421",
719 US"%s: SMTP command timeout - closing connection", smtp_active_hostname);
720 exim_exit(EXIT_FAILURE);
721 }
722
723
724
725 /*************************************************
726 * SIGTERM received *
727 *************************************************/
728
729 /* Signal handler for handling SIGTERM. Again, try to finish tidily.
730
731 Argument: signal number (SIGTERM)
732 Returns: nothing
733 */
734
735 static void
736 command_sigterm_handler(int sig)
737 {
738 sig = sig; /* Keep picky compilers happy */
739 log_write(0, LOG_MAIN, "%s closed after SIGTERM", smtp_get_connection_info());
740 if (smtp_batched_input)
741 moan_smtp_batch(NULL, "421 SIGTERM received"); /* Does not return */
742 smtp_notquit_exit(US"signal-exit", US"421",
743 US"%s: Service not available - closing connection", smtp_active_hostname);
744 exim_exit(EXIT_FAILURE);
745 }
746
747
748
749
750 #ifdef SUPPORT_PROXY
751 /*************************************************
752 * Restore socket timeout to previous value *
753 *************************************************/
754 /* If the previous value was successfully retrieved, restore
755 it before returning control to the non-proxy routines
756
757 Arguments: fd - File descriptor for input
758 get_ok - Successfully retrieved previous values
759 tvtmp - Time struct with previous values
760 vslen - Length of time struct
761 Returns: none
762 */
763 static void
764 restore_socket_timeout(int fd, int get_ok, struct timeval * tvtmp, socklen_t vslen)
765 {
766 if (get_ok == 0)
767 (void) setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS tvtmp, vslen);
768 }
769
770 /*************************************************
771 * Check if host is required proxy host *
772 *************************************************/
773 /* The function determines if inbound host will be a regular smtp host
774 or if it is configured that it must use Proxy Protocol.
775
776 Arguments: none
777 Returns: bool
778 */
779
780 static BOOL
781 check_proxy_protocol_host()
782 {
783 int rc;
784 /* Cannot configure local connection as a proxy inbound */
785 if (sender_host_address == NULL) return proxy_session;
786
787 rc = verify_check_this_host(CUSS &hosts_proxy, NULL, NULL,
788 sender_host_address, NULL);
789 if (rc == OK)
790 {
791 DEBUG(D_receive)
792 debug_printf("Detected proxy protocol configured host\n");
793 proxy_session = TRUE;
794 }
795 return proxy_session;
796 }
797
798
799 /*************************************************
800 * Setup host for proxy protocol *
801 *************************************************/
802 /* The function configures the connection based on a header from the
803 inbound host to use Proxy Protocol. The specification is very exact
804 so exit with an error if do not find the exact required pieces. This
805 includes an incorrect number of spaces separating args.
806
807 Arguments: none
808 Returns: Boolean success
809 */
810
811 static BOOL
812 setup_proxy_protocol_host()
813 {
814 union {
815 struct {
816 uschar line[108];
817 } v1;
818 struct {
819 uschar sig[12];
820 uint8_t ver_cmd;
821 uint8_t fam;
822 uint16_t len;
823 union {
824 struct { /* TCP/UDP over IPv4, len = 12 */
825 uint32_t src_addr;
826 uint32_t dst_addr;
827 uint16_t src_port;
828 uint16_t dst_port;
829 } ip4;
830 struct { /* TCP/UDP over IPv6, len = 36 */
831 uint8_t src_addr[16];
832 uint8_t dst_addr[16];
833 uint16_t src_port;
834 uint16_t dst_port;
835 } ip6;
836 struct { /* AF_UNIX sockets, len = 216 */
837 uschar src_addr[108];
838 uschar dst_addr[108];
839 } unx;
840 } addr;
841 } v2;
842 } hdr;
843
844 /* Temp variables used in PPv2 address:port parsing */
845 uint16_t tmpport;
846 char tmpip[INET_ADDRSTRLEN];
847 struct sockaddr_in tmpaddr;
848 char tmpip6[INET6_ADDRSTRLEN];
849 struct sockaddr_in6 tmpaddr6;
850
851 int get_ok = 0;
852 int size, ret;
853 int fd = fileno(smtp_in);
854 const char v2sig[12] = "\x0D\x0A\x0D\x0A\x00\x0D\x0A\x51\x55\x49\x54\x0A";
855 uschar *iptype; /* To display debug info */
856 struct timeval tv;
857 struct timeval tvtmp;
858 socklen_t vslen = sizeof(struct timeval);
859
860 /* Save current socket timeout values */
861 get_ok = getsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tvtmp, &vslen);
862
863 /* Proxy Protocol host must send header within a short time
864 (default 3 seconds) or it's considered invalid */
865 tv.tv_sec = PROXY_NEGOTIATION_TIMEOUT_SEC;
866 tv.tv_usec = PROXY_NEGOTIATION_TIMEOUT_USEC;
867 if (setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO, CS &tv, sizeof(tv)) < 0)
868 return FALSE;
869
870 do
871 {
872 /* The inbound host was declared to be a Proxy Protocol host, so
873 don't do a PEEK into the data, actually slurp it up. */
874 ret = recv(fd, &hdr, sizeof(hdr), 0);
875 }
876 while (ret == -1 && errno == EINTR);
877
878 if (ret == -1)
879 goto proxyfail;
880
881 if (ret >= 16 &&
882 memcmp(&hdr.v2, v2sig, 12) == 0)
883 {
884 uint8_t ver, cmd;
885
886 /* May 2014: haproxy combined the version and command into one byte to
887 allow two full bytes for the length field in order to proxy SSL
888 connections. SSL Proxy is not supported in this version of Exim, but
889 must still seperate values here. */
890 ver = (hdr.v2.ver_cmd & 0xf0) >> 4;
891 cmd = (hdr.v2.ver_cmd & 0x0f);
892
893 if (ver != 0x02)
894 {
895 DEBUG(D_receive) debug_printf("Invalid Proxy Protocol version: %d\n", ver);
896 goto proxyfail;
897 }
898 DEBUG(D_receive) debug_printf("Detected PROXYv2 header\n");
899 /* The v2 header will always be 16 bytes per the spec. */
900 size = 16 + hdr.v2.len;
901 if (ret < size)
902 {
903 DEBUG(D_receive) debug_printf("Truncated or too large PROXYv2 header (%d/%d)\n",
904 ret, size);
905 goto proxyfail;
906 }
907 switch (cmd)
908 {
909 case 0x01: /* PROXY command */
910 switch (hdr.v2.fam)
911 {
912 case 0x11: /* TCPv4 address type */
913 iptype = US"IPv4";
914 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.src_addr;
915 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
916 if (!string_is_ip_address(US tmpip,NULL))
917 {
918 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
919 goto proxyfail;
920 }
921 proxy_local_address = sender_host_address;
922 sender_host_address = string_copy(US tmpip);
923 tmpport = ntohs(hdr.v2.addr.ip4.src_port);
924 proxy_local_port = sender_host_port;
925 sender_host_port = tmpport;
926 /* Save dest ip/port */
927 tmpaddr.sin_addr.s_addr = hdr.v2.addr.ip4.dst_addr;
928 inet_ntop(AF_INET, &(tmpaddr.sin_addr), (char *)&tmpip, sizeof(tmpip));
929 if (!string_is_ip_address(US tmpip,NULL))
930 {
931 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
932 goto proxyfail;
933 }
934 proxy_external_address = string_copy(US tmpip);
935 tmpport = ntohs(hdr.v2.addr.ip4.dst_port);
936 proxy_external_port = tmpport;
937 goto done;
938 case 0x21: /* TCPv6 address type */
939 iptype = US"IPv6";
940 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.src_addr, 16);
941 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
942 if (!string_is_ip_address(US tmpip6,NULL))
943 {
944 DEBUG(D_receive) debug_printf("Invalid %s source IP\n", iptype);
945 goto proxyfail;
946 }
947 proxy_local_address = sender_host_address;
948 sender_host_address = string_copy(US tmpip6);
949 tmpport = ntohs(hdr.v2.addr.ip6.src_port);
950 proxy_local_port = sender_host_port;
951 sender_host_port = tmpport;
952 /* Save dest ip/port */
953 memmove(tmpaddr6.sin6_addr.s6_addr, hdr.v2.addr.ip6.dst_addr, 16);
954 inet_ntop(AF_INET6, &(tmpaddr6.sin6_addr), (char *)&tmpip6, sizeof(tmpip6));
955 if (!string_is_ip_address(US tmpip6,NULL))
956 {
957 DEBUG(D_receive) debug_printf("Invalid %s dest port\n", iptype);
958 goto proxyfail;
959 }
960 proxy_external_address = string_copy(US tmpip6);
961 tmpport = ntohs(hdr.v2.addr.ip6.dst_port);
962 proxy_external_port = tmpport;
963 goto done;
964 default:
965 DEBUG(D_receive)
966 debug_printf("Unsupported PROXYv2 connection type: 0x%02x\n",
967 hdr.v2.fam);
968 goto proxyfail;
969 }
970 /* Unsupported protocol, keep local connection address */
971 break;
972 case 0x00: /* LOCAL command */
973 /* Keep local connection address for LOCAL */
974 break;
975 default:
976 DEBUG(D_receive)
977 debug_printf("Unsupported PROXYv2 command: 0x%x\n", cmd);
978 goto proxyfail;
979 }
980 }
981 else if (ret >= 8 &&
982 memcmp(hdr.v1.line, "PROXY", 5) == 0)
983 {
984 uschar *p = string_copy(hdr.v1.line);
985 uschar *end = memchr(p, '\r', ret - 1);
986 uschar *sp; /* Utility variables follow */
987 int tmp_port;
988 char *endc;
989
990 if (!end || end[1] != '\n')
991 {
992 DEBUG(D_receive) debug_printf("Partial or invalid PROXY header\n");
993 goto proxyfail;
994 }
995 *end = '\0'; /* Terminate the string */
996 size = end + 2 - hdr.v1.line; /* Skip header + CRLF */
997 DEBUG(D_receive) debug_printf("Detected PROXYv1 header\n");
998 /* Step through the string looking for the required fields. Ensure
999 strict adherance to required formatting, exit for any error. */
1000 p += 5;
1001 if (!isspace(*(p++)))
1002 {
1003 DEBUG(D_receive) debug_printf("Missing space after PROXY command\n");
1004 goto proxyfail;
1005 }
1006 if (!Ustrncmp(p, CCS"TCP4", 4))
1007 iptype = US"IPv4";
1008 else if (!Ustrncmp(p,CCS"TCP6", 4))
1009 iptype = US"IPv6";
1010 else if (!Ustrncmp(p,CCS"UNKNOWN", 7))
1011 {
1012 iptype = US"Unknown";
1013 goto done;
1014 }
1015 else
1016 {
1017 DEBUG(D_receive) debug_printf("Invalid TCP type\n");
1018 goto proxyfail;
1019 }
1020
1021 p += Ustrlen(iptype);
1022 if (!isspace(*(p++)))
1023 {
1024 DEBUG(D_receive) debug_printf("Missing space after TCP4/6 command\n");
1025 goto proxyfail;
1026 }
1027 /* Find the end of the arg */
1028 if ((sp = Ustrchr(p, ' ')) == NULL)
1029 {
1030 DEBUG(D_receive)
1031 debug_printf("Did not find proxied src %s\n", iptype);
1032 goto proxyfail;
1033 }
1034 *sp = '\0';
1035 if(!string_is_ip_address(p,NULL))
1036 {
1037 DEBUG(D_receive)
1038 debug_printf("Proxied src arg is not an %s address\n", iptype);
1039 goto proxyfail;
1040 }
1041 proxy_local_address = sender_host_address;
1042 sender_host_address = p;
1043 p = sp + 1;
1044 if ((sp = Ustrchr(p, ' ')) == NULL)
1045 {
1046 DEBUG(D_receive)
1047 debug_printf("Did not find proxy dest %s\n", iptype);
1048 goto proxyfail;
1049 }
1050 *sp = '\0';
1051 if(!string_is_ip_address(p,NULL))
1052 {
1053 DEBUG(D_receive)
1054 debug_printf("Proxy dest arg is not an %s address\n", iptype);
1055 goto proxyfail;
1056 }
1057 proxy_external_address = p;
1058 p = sp + 1;
1059 if ((sp = Ustrchr(p, ' ')) == NULL)
1060 {
1061 DEBUG(D_receive) debug_printf("Did not find proxied src port\n");
1062 goto proxyfail;
1063 }
1064 *sp = '\0';
1065 tmp_port = strtol(CCS p,&endc,10);
1066 if (*endc || tmp_port == 0)
1067 {
1068 DEBUG(D_receive)
1069 debug_printf("Proxied src port '%s' not an integer\n", p);
1070 goto proxyfail;
1071 }
1072 proxy_local_port = sender_host_port;
1073 sender_host_port = tmp_port;
1074 p = sp + 1;
1075 if ((sp = Ustrchr(p, '\0')) == NULL)
1076 {
1077 DEBUG(D_receive) debug_printf("Did not find proxy dest port\n");
1078 goto proxyfail;
1079 }
1080 tmp_port = strtol(CCS p,&endc,10);
1081 if (*endc || tmp_port == 0)
1082 {
1083 DEBUG(D_receive)
1084 debug_printf("Proxy dest port '%s' not an integer\n", p);
1085 goto proxyfail;
1086 }
1087 proxy_external_port = tmp_port;
1088 /* Already checked for /r /n above. Good V1 header received. */
1089 goto done;
1090 }
1091 else
1092 {
1093 /* Wrong protocol */
1094 DEBUG(D_receive) debug_printf("Invalid proxy protocol version negotiation\n");
1095 goto proxyfail;
1096 }
1097
1098 proxyfail:
1099 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1100 /* Don't flush any potential buffer contents. Any input should cause a
1101 synchronization failure */
1102 return FALSE;
1103
1104 done:
1105 restore_socket_timeout(fd, get_ok, &tvtmp, vslen);
1106 DEBUG(D_receive)
1107 debug_printf("Valid %s sender from Proxy Protocol header\n", iptype);
1108 return proxy_session;
1109 }
1110 #endif
1111
1112 /*************************************************
1113 * Read one command line *
1114 *************************************************/
1115
1116 /* Strictly, SMTP commands coming over the net are supposed to end with CRLF.
1117 There are sites that don't do this, and in any case internal SMTP probably
1118 should check only for LF. Consequently, we check here for LF only. The line
1119 ends up with [CR]LF removed from its end. If we get an overlong line, treat as
1120 an unknown command. The command is read into the global smtp_cmd_buffer so that
1121 it is available via $smtp_command.
1122
1123 The character reading routine sets up a timeout for each block actually read
1124 from the input (which may contain more than one command). We set up a special
1125 signal handler that closes down the session on a timeout. Control does not
1126 return when it runs.
1127
1128 Arguments:
1129 check_sync if TRUE, check synchronization rules if global option is TRUE
1130
1131 Returns: a code identifying the command (enumerated above)
1132 */
1133
1134 static int
1135 smtp_read_command(BOOL check_sync)
1136 {
1137 int c;
1138 int ptr = 0;
1139 smtp_cmd_list *p;
1140 BOOL hadnull = FALSE;
1141
1142 os_non_restarting_signal(SIGALRM, command_timeout_handler);
1143
1144 while ((c = (receive_getc)()) != '\n' && c != EOF)
1145 {
1146 if (ptr >= smtp_cmd_buffer_size)
1147 {
1148 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1149 return OTHER_CMD;
1150 }
1151 if (c == 0)
1152 {
1153 hadnull = TRUE;
1154 c = '?';
1155 }
1156 smtp_cmd_buffer[ptr++] = c;
1157 }
1158
1159 receive_linecount++; /* For BSMTP errors */
1160 os_non_restarting_signal(SIGALRM, sigalrm_handler);
1161
1162 /* If hit end of file, return pseudo EOF command. Whether we have a
1163 part-line already read doesn't matter, since this is an error state. */
1164
1165 if (c == EOF) return EOF_CMD;
1166
1167 /* Remove any CR and white space at the end of the line, and terminate the
1168 string. */
1169
1170 while (ptr > 0 && isspace(smtp_cmd_buffer[ptr-1])) ptr--;
1171 smtp_cmd_buffer[ptr] = 0;
1172
1173 DEBUG(D_receive) debug_printf("SMTP<< %s\n", smtp_cmd_buffer);
1174
1175 /* NULLs are not allowed in SMTP commands */
1176
1177 if (hadnull) return BADCHAR_CMD;
1178
1179 /* Scan command list and return identity, having set the data pointer
1180 to the start of the actual data characters. Check for SMTP synchronization
1181 if required. */
1182
1183 for (p = cmd_list; p < cmd_list_end; p++)
1184 {
1185 #ifdef SUPPORT_PROXY
1186 /* Only allow QUIT command if Proxy Protocol parsing failed */
1187 if (proxy_session && proxy_session_failed)
1188 {
1189 if (p->cmd != QUIT_CMD)
1190 continue;
1191 }
1192 #endif
1193 if ( p->len
1194 && strncmpic(smtp_cmd_buffer, US p->name, p->len) == 0
1195 && ( smtp_cmd_buffer[p->len-1] == ':' /* "mail from:" or "rcpt to:" */
1196 || smtp_cmd_buffer[p->len] == 0
1197 || smtp_cmd_buffer[p->len] == ' '
1198 ) )
1199 {
1200 if (smtp_inptr < smtp_inend && /* Outstanding input */
1201 p->cmd < sync_cmd_limit && /* Command should sync */
1202 check_sync && /* Local flag set */
1203 smtp_enforce_sync && /* Global flag set */
1204 sender_host_address != NULL && /* Not local input */
1205 !sender_host_notsocket) /* Really is a socket */
1206 return BADSYN_CMD;
1207
1208 /* The variables $smtp_command and $smtp_command_argument point into the
1209 unmodified input buffer. A copy of the latter is taken for actual
1210 processing, so that it can be chopped up into separate parts if necessary,
1211 for example, when processing a MAIL command options such as SIZE that can
1212 follow the sender address. */
1213
1214 smtp_cmd_argument = smtp_cmd_buffer + p->len;
1215 while (isspace(*smtp_cmd_argument)) smtp_cmd_argument++;
1216 Ustrcpy(smtp_data_buffer, smtp_cmd_argument);
1217 smtp_cmd_data = smtp_data_buffer;
1218
1219 /* Count non-mail commands from those hosts that are controlled in this
1220 way. The default is all hosts. We don't waste effort checking the list
1221 until we get a non-mail command, but then cache the result to save checking
1222 again. If there's a DEFER while checking the host, assume it's in the list.
1223
1224 Note that one instance of RSET, EHLO/HELO, and STARTTLS is allowed at the
1225 start of each incoming message by fiddling with the value in the table. */
1226
1227 if (!p->is_mail_cmd)
1228 {
1229 if (count_nonmail == TRUE_UNSET) count_nonmail =
1230 verify_check_host(&smtp_accept_max_nonmail_hosts) != FAIL;
1231 if (count_nonmail && ++nonmail_command_count > smtp_accept_max_nonmail)
1232 return TOO_MANY_NONMAIL_CMD;
1233 }
1234
1235 /* If there is data for a command that does not expect it, generate the
1236 error here. */
1237
1238 return (p->has_arg || *smtp_cmd_data == 0)? p->cmd : BADARG_CMD;
1239 }
1240 }
1241
1242 #ifdef SUPPORT_PROXY
1243 /* Only allow QUIT command if Proxy Protocol parsing failed */
1244 if (proxy_session && proxy_session_failed)
1245 return PROXY_FAIL_IGNORE_CMD;
1246 #endif
1247
1248 /* Enforce synchronization for unknown commands */
1249
1250 if (smtp_inptr < smtp_inend && /* Outstanding input */
1251 check_sync && /* Local flag set */
1252 smtp_enforce_sync && /* Global flag set */
1253 sender_host_address != NULL && /* Not local input */
1254 !sender_host_notsocket) /* Really is a socket */
1255 return BADSYN_CMD;
1256
1257 return OTHER_CMD;
1258 }
1259
1260
1261
1262 /*************************************************
1263 * Recheck synchronization *
1264 *************************************************/
1265
1266 /* Synchronization checks can never be perfect because a packet may be on its
1267 way but not arrived when the check is done. Such checks can in any case only be
1268 done when TLS is not in use. Normally, the checks happen when commands are
1269 read: Exim ensures that there is no more input in the input buffer. In normal
1270 cases, the response to the command will be fast, and there is no further check.
1271
1272 However, for some commands an ACL is run, and that can include delays. In those
1273 cases, it is useful to do another check on the input just before sending the
1274 response. This also applies at the start of a connection. This function does
1275 that check by means of the select() function, as long as the facility is not
1276 disabled or inappropriate. A failure of select() is ignored.
1277
1278 When there is unwanted input, we read it so that it appears in the log of the
1279 error.
1280
1281 Arguments: none
1282 Returns: TRUE if all is well; FALSE if there is input pending
1283 */
1284
1285 static BOOL
1286 check_sync(void)
1287 {
1288 int fd, rc;
1289 fd_set fds;
1290 struct timeval tzero;
1291
1292 if (!smtp_enforce_sync || sender_host_address == NULL ||
1293 sender_host_notsocket || tls_in.active >= 0)
1294 return TRUE;
1295
1296 fd = fileno(smtp_in);
1297 FD_ZERO(&fds);
1298 FD_SET(fd, &fds);
1299 tzero.tv_sec = 0;
1300 tzero.tv_usec = 0;
1301 rc = select(fd + 1, (SELECT_ARG2_TYPE *)&fds, NULL, NULL, &tzero);
1302
1303 if (rc <= 0) return TRUE; /* Not ready to read */
1304 rc = smtp_getc();
1305 if (rc < 0) return TRUE; /* End of file or error */
1306
1307 smtp_ungetc(rc);
1308 rc = smtp_inend - smtp_inptr;
1309 if (rc > 150) rc = 150;
1310 smtp_inptr[rc] = 0;
1311 return FALSE;
1312 }
1313
1314
1315
1316 /*************************************************
1317 * Forced closedown of call *
1318 *************************************************/
1319
1320 /* This function is called from log.c when Exim is dying because of a serious
1321 disaster, and also from some other places. If an incoming non-batched SMTP
1322 channel is open, it swallows the rest of the incoming message if in the DATA
1323 phase, sends the reply string, and gives an error to all subsequent commands
1324 except QUIT. The existence of an SMTP call is detected by the non-NULLness of
1325 smtp_in.
1326
1327 Arguments:
1328 message SMTP reply string to send, excluding the code
1329
1330 Returns: nothing
1331 */
1332
1333 void
1334 smtp_closedown(uschar *message)
1335 {
1336 if (smtp_in == NULL || smtp_batched_input) return;
1337 receive_swallow_smtp();
1338 smtp_printf("421 %s\r\n", message);
1339
1340 for (;;) switch(smtp_read_command(FALSE))
1341 {
1342 case EOF_CMD:
1343 return;
1344
1345 case QUIT_CMD:
1346 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
1347 mac_smtp_fflush();
1348 return;
1349
1350 case RSET_CMD:
1351 smtp_printf("250 Reset OK\r\n");
1352 break;
1353
1354 default:
1355 smtp_printf("421 %s\r\n", message);
1356 break;
1357 }
1358 }
1359
1360
1361
1362
1363 /*************************************************
1364 * Set up connection info for logging *
1365 *************************************************/
1366
1367 /* This function is called when logging information about an SMTP connection.
1368 It sets up appropriate source information, depending on the type of connection.
1369 If sender_fullhost is NULL, we are at a very early stage of the connection;
1370 just use the IP address.
1371
1372 Argument: none
1373 Returns: a string describing the connection
1374 */
1375
1376 uschar *
1377 smtp_get_connection_info(void)
1378 {
1379 uschar *hostname = (sender_fullhost == NULL)?
1380 sender_host_address : sender_fullhost;
1381
1382 if (host_checking)
1383 return string_sprintf("SMTP connection from %s", hostname);
1384
1385 if (sender_host_unknown || sender_host_notsocket)
1386 return string_sprintf("SMTP connection from %s", sender_ident);
1387
1388 if (is_inetd)
1389 return string_sprintf("SMTP connection from %s (via inetd)", hostname);
1390
1391 if (LOGGING(incoming_interface) && interface_address != NULL)
1392 return string_sprintf("SMTP connection from %s I=[%s]:%d", hostname,
1393 interface_address, interface_port);
1394
1395 return string_sprintf("SMTP connection from %s", hostname);
1396 }
1397
1398
1399
1400 #ifdef SUPPORT_TLS
1401 /* Append TLS-related information to a log line
1402
1403 Arguments:
1404 s String under construction: allocated string to extend, or NULL
1405 sizep Pointer to current allocation size (update on return), or NULL
1406 ptrp Pointer to index for new entries in string (update on return), or NULL
1407
1408 Returns: Allocated string or NULL
1409 */
1410 static uschar *
1411 s_tlslog(uschar * s, int * sizep, int * ptrp)
1412 {
1413 int size = sizep ? *sizep : 0;
1414 int ptr = ptrp ? *ptrp : 0;
1415
1416 if (LOGGING(tls_cipher) && tls_in.cipher != NULL)
1417 s = string_append(s, &size, &ptr, 2, US" X=", tls_in.cipher);
1418 if (LOGGING(tls_certificate_verified) && tls_in.cipher != NULL)
1419 s = string_append(s, &size, &ptr, 2, US" CV=",
1420 tls_in.certificate_verified? "yes":"no");
1421 if (LOGGING(tls_peerdn) && tls_in.peerdn != NULL)
1422 s = string_append(s, &size, &ptr, 3, US" DN=\"",
1423 string_printing(tls_in.peerdn), US"\"");
1424 if (LOGGING(tls_sni) && tls_in.sni != NULL)
1425 s = string_append(s, &size, &ptr, 3, US" SNI=\"",
1426 string_printing(tls_in.sni), US"\"");
1427
1428 if (s)
1429 {
1430 s[ptr] = '\0';
1431 if (sizep) *sizep = size;
1432 if (ptrp) *ptrp = ptr;
1433 }
1434 return s;
1435 }
1436 #endif
1437
1438 /*************************************************
1439 * Log lack of MAIL if so configured *
1440 *************************************************/
1441
1442 /* This function is called when an SMTP session ends. If the log selector
1443 smtp_no_mail is set, write a log line giving some details of what has happened
1444 in the SMTP session.
1445
1446 Arguments: none
1447 Returns: nothing
1448 */
1449
1450 void
1451 smtp_log_no_mail(void)
1452 {
1453 int size, ptr, i;
1454 uschar *s, *sep;
1455
1456 if (smtp_mailcmd_count > 0 || !LOGGING(smtp_no_mail))
1457 return;
1458
1459 s = NULL;
1460 size = ptr = 0;
1461
1462 if (sender_host_authenticated != NULL)
1463 {
1464 s = string_append(s, &size, &ptr, 2, US" A=", sender_host_authenticated);
1465 if (authenticated_id != NULL)
1466 s = string_append(s, &size, &ptr, 2, US":", authenticated_id);
1467 }
1468
1469 #ifdef SUPPORT_TLS
1470 s = s_tlslog(s, &size, &ptr);
1471 #endif
1472
1473 sep = (smtp_connection_had[SMTP_HBUFF_SIZE-1] != SCH_NONE)?
1474 US" C=..." : US" C=";
1475 for (i = smtp_ch_index; i < SMTP_HBUFF_SIZE; i++)
1476 {
1477 if (smtp_connection_had[i] != SCH_NONE)
1478 {
1479 s = string_append(s, &size, &ptr, 2, sep,
1480 smtp_names[smtp_connection_had[i]]);
1481 sep = US",";
1482 }
1483 }
1484
1485 for (i = 0; i < smtp_ch_index; i++)
1486 {
1487 s = string_append(s, &size, &ptr, 2, sep, smtp_names[smtp_connection_had[i]]);
1488 sep = US",";
1489 }
1490
1491 if (s != NULL) s[ptr] = 0; else s = US"";
1492 log_write(0, LOG_MAIN, "no MAIL in SMTP connection from %s D=%s%s",
1493 host_and_ident(FALSE),
1494 readconf_printtime( (int) ((long)time(NULL) - (long)smtp_connection_start)),
1495 s);
1496 }
1497
1498
1499
1500 /*************************************************
1501 * Check HELO line and set sender_helo_name *
1502 *************************************************/
1503
1504 /* Check the format of a HELO line. The data for HELO/EHLO is supposed to be
1505 the domain name of the sending host, or an ip literal in square brackets. The
1506 arrgument is placed in sender_helo_name, which is in malloc store, because it
1507 must persist over multiple incoming messages. If helo_accept_junk is set, this
1508 host is permitted to send any old junk (needed for some broken hosts).
1509 Otherwise, helo_allow_chars can be used for rogue characters in general
1510 (typically people want to let in underscores).
1511
1512 Argument:
1513 s the data portion of the line (already past any white space)
1514
1515 Returns: TRUE or FALSE
1516 */
1517
1518 static BOOL
1519 check_helo(uschar *s)
1520 {
1521 uschar *start = s;
1522 uschar *end = s + Ustrlen(s);
1523 BOOL yield = helo_accept_junk;
1524
1525 /* Discard any previous helo name */
1526
1527 if (sender_helo_name != NULL)
1528 {
1529 store_free(sender_helo_name);
1530 sender_helo_name = NULL;
1531 }
1532
1533 /* Skip tests if junk is permitted. */
1534
1535 if (!yield)
1536 {
1537 /* Allow the new standard form for IPv6 address literals, namely,
1538 [IPv6:....], and because someone is bound to use it, allow an equivalent
1539 IPv4 form. Allow plain addresses as well. */
1540
1541 if (*s == '[')
1542 {
1543 if (end[-1] == ']')
1544 {
1545 end[-1] = 0;
1546 if (strncmpic(s, US"[IPv6:", 6) == 0)
1547 yield = (string_is_ip_address(s+6, NULL) == 6);
1548 else if (strncmpic(s, US"[IPv4:", 6) == 0)
1549 yield = (string_is_ip_address(s+6, NULL) == 4);
1550 else
1551 yield = (string_is_ip_address(s+1, NULL) != 0);
1552 end[-1] = ']';
1553 }
1554 }
1555
1556 /* Non-literals must be alpha, dot, hyphen, plus any non-valid chars
1557 that have been configured (usually underscore - sigh). */
1558
1559 else if (*s != 0)
1560 {
1561 yield = TRUE;
1562 while (*s != 0)
1563 {
1564 if (!isalnum(*s) && *s != '.' && *s != '-' &&
1565 Ustrchr(helo_allow_chars, *s) == NULL)
1566 {
1567 yield = FALSE;
1568 break;
1569 }
1570 s++;
1571 }
1572 }
1573 }
1574
1575 /* Save argument if OK */
1576
1577 if (yield) sender_helo_name = string_copy_malloc(start);
1578 return yield;
1579 }
1580
1581
1582
1583
1584
1585 /*************************************************
1586 * Extract SMTP command option *
1587 *************************************************/
1588
1589 /* This function picks the next option setting off the end of smtp_cmd_data. It
1590 is called for MAIL FROM and RCPT TO commands, to pick off the optional ESMTP
1591 things that can appear there.
1592
1593 Arguments:
1594 name point this at the name
1595 value point this at the data string
1596
1597 Returns: TRUE if found an option
1598 */
1599
1600 static BOOL
1601 extract_option(uschar **name, uschar **value)
1602 {
1603 uschar *n;
1604 uschar *v = smtp_cmd_data + Ustrlen(smtp_cmd_data) - 1;
1605 while (isspace(*v)) v--;
1606 v[1] = 0;
1607 while (v > smtp_cmd_data && *v != '=' && !isspace(*v)) v--;
1608
1609 n = v;
1610 if (*v == '=')
1611 {
1612 while(isalpha(n[-1])) n--;
1613 /* RFC says SP, but TAB seen in wild and other major MTAs accept it */
1614 if (!isspace(n[-1])) return FALSE;
1615 n[-1] = 0;
1616 }
1617 else
1618 {
1619 n++;
1620 if (v == smtp_cmd_data) return FALSE;
1621 }
1622 *v++ = 0;
1623 *name = n;
1624 *value = v;
1625 return TRUE;
1626 }
1627
1628
1629
1630
1631
1632 /*************************************************
1633 * Reset for new message *
1634 *************************************************/
1635
1636 /* This function is called whenever the SMTP session is reset from
1637 within either of the setup functions.
1638
1639 Argument: the stacking pool storage reset point
1640 Returns: nothing
1641 */
1642
1643 static void
1644 smtp_reset(void *reset_point)
1645 {
1646 store_reset(reset_point);
1647 recipients_list = NULL;
1648 rcpt_count = rcpt_defer_count = rcpt_fail_count =
1649 raw_recipients_count = recipients_count = recipients_list_max = 0;
1650 cancel_cutthrough_connection("smtp reset");
1651 message_linecount = 0;
1652 message_size = -1;
1653 acl_added_headers = NULL;
1654 acl_removed_headers = NULL;
1655 queue_only_policy = FALSE;
1656 rcpt_smtp_response = NULL;
1657 rcpt_smtp_response_same = TRUE;
1658 rcpt_in_progress = FALSE;
1659 deliver_freeze = FALSE; /* Can be set by ACL */
1660 freeze_tell = freeze_tell_config; /* Can be set by ACL */
1661 fake_response = OK; /* Can be set by ACL */
1662 #ifdef WITH_CONTENT_SCAN
1663 no_mbox_unspool = FALSE; /* Can be set by ACL */
1664 #endif
1665 submission_mode = FALSE; /* Can be set by ACL */
1666 suppress_local_fixups = suppress_local_fixups_default; /* Can be set by ACL */
1667 active_local_from_check = local_from_check; /* Can be set by ACL */
1668 active_local_sender_retain = local_sender_retain; /* Can be set by ACL */
1669 sender_address = NULL;
1670 submission_name = NULL; /* Can be set by ACL */
1671 raw_sender = NULL; /* After SMTP rewrite, before qualifying */
1672 sender_address_unrewritten = NULL; /* Set only after verify rewrite */
1673 sender_verified_list = NULL; /* No senders verified */
1674 memset(sender_address_cache, 0, sizeof(sender_address_cache));
1675 memset(sender_domain_cache, 0, sizeof(sender_domain_cache));
1676
1677 authenticated_sender = NULL;
1678 #ifdef EXPERIMENTAL_BRIGHTMAIL
1679 bmi_run = 0;
1680 bmi_verdicts = NULL;
1681 #endif
1682 #ifndef DISABLE_DKIM
1683 dkim_signers = NULL;
1684 dkim_disable_verify = FALSE;
1685 dkim_collect_input = FALSE;
1686 #endif
1687 dsn_ret = 0;
1688 dsn_envid = NULL;
1689 #ifndef DISABLE_PRDR
1690 prdr_requested = FALSE;
1691 #endif
1692 #ifdef EXPERIMENTAL_SPF
1693 spf_header_comment = NULL;
1694 spf_received = NULL;
1695 spf_result = NULL;
1696 spf_smtp_comment = NULL;
1697 #endif
1698 #ifdef SUPPORT_I18N
1699 message_smtputf8 = FALSE;
1700 #endif
1701 body_linecount = body_zerocount = 0;
1702
1703 sender_rate = sender_rate_limit = sender_rate_period = NULL;
1704 ratelimiters_mail = NULL; /* Updated by ratelimit ACL condition */
1705 /* Note that ratelimiters_conn persists across resets. */
1706
1707 /* Reset message ACL variables */
1708
1709 acl_var_m = NULL;
1710
1711 /* The message body variables use malloc store. They may be set if this is
1712 not the first message in an SMTP session and the previous message caused them
1713 to be referenced in an ACL. */
1714
1715 if (message_body != NULL)
1716 {
1717 store_free(message_body);
1718 message_body = NULL;
1719 }
1720
1721 if (message_body_end != NULL)
1722 {
1723 store_free(message_body_end);
1724 message_body_end = NULL;
1725 }
1726
1727 /* Warning log messages are also saved in malloc store. They are saved to avoid
1728 repetition in the same message, but it seems right to repeat them for different
1729 messages. */
1730
1731 while (acl_warn_logged != NULL)
1732 {
1733 string_item *this = acl_warn_logged;
1734 acl_warn_logged = acl_warn_logged->next;
1735 store_free(this);
1736 }
1737 }
1738
1739
1740
1741
1742
1743 /*************************************************
1744 * Initialize for incoming batched SMTP message *
1745 *************************************************/
1746
1747 /* This function is called from smtp_setup_msg() in the case when
1748 smtp_batched_input is true. This happens when -bS is used to pass a whole batch
1749 of messages in one file with SMTP commands between them. All errors must be
1750 reported by sending a message, and only MAIL FROM, RCPT TO, and DATA are
1751 relevant. After an error on a sender, or an invalid recipient, the remainder
1752 of the message is skipped. The value of received_protocol is already set.
1753
1754 Argument: none
1755 Returns: > 0 message successfully started (reached DATA)
1756 = 0 QUIT read or end of file reached
1757 < 0 should not occur
1758 */
1759
1760 static int
1761 smtp_setup_batch_msg(void)
1762 {
1763 int done = 0;
1764 void *reset_point = store_get(0);
1765
1766 /* Save the line count at the start of each transaction - single commands
1767 like HELO and RSET count as whole transactions. */
1768
1769 bsmtp_transaction_linecount = receive_linecount;
1770
1771 if ((receive_feof)()) return 0; /* Treat EOF as QUIT */
1772
1773 smtp_reset(reset_point); /* Reset for start of message */
1774
1775 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
1776 value. The values are 2 larger than the required yield of the function. */
1777
1778 while (done <= 0)
1779 {
1780 uschar *errmess;
1781 uschar *recipient = NULL;
1782 int start, end, sender_domain, recipient_domain;
1783
1784 switch(smtp_read_command(FALSE))
1785 {
1786 /* The HELO/EHLO commands set sender_address_helo if they have
1787 valid data; otherwise they are ignored, except that they do
1788 a reset of the state. */
1789
1790 case HELO_CMD:
1791 case EHLO_CMD:
1792
1793 check_helo(smtp_cmd_data);
1794 /* Fall through */
1795
1796 case RSET_CMD:
1797 smtp_reset(reset_point);
1798 bsmtp_transaction_linecount = receive_linecount;
1799 break;
1800
1801
1802 /* The MAIL FROM command requires an address as an operand. All we
1803 do here is to parse it for syntactic correctness. The form "<>" is
1804 a special case which converts into an empty string. The start/end
1805 pointers in the original are not used further for this address, as
1806 it is the canonical extracted address which is all that is kept. */
1807
1808 case MAIL_CMD:
1809 smtp_mailcmd_count++; /* Count for no-mail log */
1810 if (sender_address != NULL)
1811 /* The function moan_smtp_batch() does not return. */
1812 moan_smtp_batch(smtp_cmd_buffer, "503 Sender already given");
1813
1814 if (smtp_cmd_data[0] == 0)
1815 /* The function moan_smtp_batch() does not return. */
1816 moan_smtp_batch(smtp_cmd_buffer, "501 MAIL FROM must have an address operand");
1817
1818 /* Reset to start of message */
1819
1820 smtp_reset(reset_point);
1821
1822 /* Apply SMTP rewrite */
1823
1824 raw_sender = ((rewrite_existflags & rewrite_smtp) != 0)?
1825 rewrite_one(smtp_cmd_data, rewrite_smtp|rewrite_smtp_sender, NULL, FALSE,
1826 US"", global_rewrite_rules) : smtp_cmd_data;
1827
1828 /* Extract the address; the TRUE flag allows <> as valid */
1829
1830 raw_sender =
1831 parse_extract_address(raw_sender, &errmess, &start, &end, &sender_domain,
1832 TRUE);
1833
1834 if (raw_sender == NULL)
1835 /* The function moan_smtp_batch() does not return. */
1836 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1837
1838 sender_address = string_copy(raw_sender);
1839
1840 /* Qualify unqualified sender addresses if permitted to do so. */
1841
1842 if (sender_domain == 0 && sender_address[0] != 0 && sender_address[0] != '@')
1843 {
1844 if (allow_unqualified_sender)
1845 {
1846 sender_address = rewrite_address_qualify(sender_address, FALSE);
1847 DEBUG(D_receive) debug_printf("unqualified address %s accepted "
1848 "and rewritten\n", raw_sender);
1849 }
1850 /* The function moan_smtp_batch() does not return. */
1851 else moan_smtp_batch(smtp_cmd_buffer, "501 sender address must contain "
1852 "a domain");
1853 }
1854 break;
1855
1856
1857 /* The RCPT TO command requires an address as an operand. All we do
1858 here is to parse it for syntactic correctness. There may be any number
1859 of RCPT TO commands, specifying multiple senders. We build them all into
1860 a data structure that is in argc/argv format. The start/end values
1861 given by parse_extract_address are not used, as we keep only the
1862 extracted address. */
1863
1864 case RCPT_CMD:
1865 if (sender_address == NULL)
1866 /* The function moan_smtp_batch() does not return. */
1867 moan_smtp_batch(smtp_cmd_buffer, "503 No sender yet given");
1868
1869 if (smtp_cmd_data[0] == 0)
1870 /* The function moan_smtp_batch() does not return. */
1871 moan_smtp_batch(smtp_cmd_buffer, "501 RCPT TO must have an address operand");
1872
1873 /* Check maximum number allowed */
1874
1875 if (recipients_max > 0 && recipients_count + 1 > recipients_max)
1876 /* The function moan_smtp_batch() does not return. */
1877 moan_smtp_batch(smtp_cmd_buffer, "%s too many recipients",
1878 recipients_max_reject? "552": "452");
1879
1880 /* Apply SMTP rewrite, then extract address. Don't allow "<>" as a
1881 recipient address */
1882
1883 recipient = rewrite_existflags & rewrite_smtp
1884 ? rewrite_one(smtp_cmd_data, rewrite_smtp, NULL, FALSE, US"",
1885 global_rewrite_rules)
1886 : smtp_cmd_data;
1887
1888 recipient = parse_extract_address(recipient, &errmess, &start, &end,
1889 &recipient_domain, FALSE);
1890
1891 if (!recipient)
1892 /* The function moan_smtp_batch() does not return. */
1893 moan_smtp_batch(smtp_cmd_buffer, "501 %s", errmess);
1894
1895 /* If the recipient address is unqualified, qualify it if permitted. Then
1896 add it to the list of recipients. */
1897
1898 if (recipient_domain == 0)
1899 {
1900 if (allow_unqualified_recipient)
1901 {
1902 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
1903 recipient);
1904 recipient = rewrite_address_qualify(recipient, TRUE);
1905 }
1906 /* The function moan_smtp_batch() does not return. */
1907 else moan_smtp_batch(smtp_cmd_buffer, "501 recipient address must contain "
1908 "a domain");
1909 }
1910 receive_add_recipient(recipient, -1);
1911 break;
1912
1913
1914 /* The DATA command is legal only if it follows successful MAIL FROM
1915 and RCPT TO commands. This function is complete when a valid DATA
1916 command is encountered. */
1917
1918 case DATA_CMD:
1919 if (sender_address == NULL || recipients_count <= 0)
1920 {
1921 /* The function moan_smtp_batch() does not return. */
1922 if (sender_address == NULL)
1923 moan_smtp_batch(smtp_cmd_buffer,
1924 "503 MAIL FROM:<sender> command must precede DATA");
1925 else
1926 moan_smtp_batch(smtp_cmd_buffer,
1927 "503 RCPT TO:<recipient> must precede DATA");
1928 }
1929 else
1930 {
1931 done = 3; /* DATA successfully achieved */
1932 message_ended = END_NOTENDED; /* Indicate in middle of message */
1933 }
1934 break;
1935
1936
1937 /* The VRFY, EXPN, HELP, ETRN, and NOOP commands are ignored. */
1938
1939 case VRFY_CMD:
1940 case EXPN_CMD:
1941 case HELP_CMD:
1942 case NOOP_CMD:
1943 case ETRN_CMD:
1944 bsmtp_transaction_linecount = receive_linecount;
1945 break;
1946
1947
1948 case EOF_CMD:
1949 case QUIT_CMD:
1950 done = 2;
1951 break;
1952
1953
1954 case BADARG_CMD:
1955 /* The function moan_smtp_batch() does not return. */
1956 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected argument data");
1957 break;
1958
1959
1960 case BADCHAR_CMD:
1961 /* The function moan_smtp_batch() does not return. */
1962 moan_smtp_batch(smtp_cmd_buffer, "501 Unexpected NULL in SMTP command");
1963 break;
1964
1965
1966 default:
1967 /* The function moan_smtp_batch() does not return. */
1968 moan_smtp_batch(smtp_cmd_buffer, "500 Command unrecognized");
1969 break;
1970 }
1971 }
1972
1973 return done - 2; /* Convert yield values */
1974 }
1975
1976
1977
1978
1979 /*************************************************
1980 * Start an SMTP session *
1981 *************************************************/
1982
1983 /* This function is called at the start of an SMTP session. Thereafter,
1984 smtp_setup_msg() is called to initiate each separate message. This
1985 function does host-specific testing, and outputs the banner line.
1986
1987 Arguments: none
1988 Returns: FALSE if the session can not continue; something has
1989 gone wrong, or the connection to the host is blocked
1990 */
1991
1992 BOOL
1993 smtp_start_session(void)
1994 {
1995 int size = 256;
1996 int ptr, esclen;
1997 uschar *user_msg, *log_msg;
1998 uschar *code, *esc;
1999 uschar *p, *s, *ss;
2000
2001 smtp_connection_start = time(NULL);
2002 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
2003 smtp_connection_had[smtp_ch_index] = SCH_NONE;
2004 smtp_ch_index = 0;
2005
2006 /* Default values for certain variables */
2007
2008 helo_seen = esmtp = helo_accept_junk = FALSE;
2009 smtp_mailcmd_count = 0;
2010 count_nonmail = TRUE_UNSET;
2011 synprot_error_count = unknown_command_count = nonmail_command_count = 0;
2012 smtp_delay_mail = smtp_rlm_base;
2013 auth_advertised = FALSE;
2014 pipelining_advertised = FALSE;
2015 pipelining_enable = TRUE;
2016 sync_cmd_limit = NON_SYNC_CMD_NON_PIPELINING;
2017 smtp_exit_function_called = FALSE; /* For avoiding loop in not-quit exit */
2018
2019 /* If receiving by -bs from a trusted user, or testing with -bh, we allow
2020 authentication settings from -oMaa to remain in force. */
2021
2022 if (!host_checking && !sender_host_notsocket) sender_host_authenticated = NULL;
2023 authenticated_by = NULL;
2024
2025 #ifdef SUPPORT_TLS
2026 tls_in.cipher = tls_in.peerdn = NULL;
2027 tls_in.ourcert = tls_in.peercert = NULL;
2028 tls_in.sni = NULL;
2029 tls_in.ocsp = OCSP_NOT_REQ;
2030 tls_advertised = FALSE;
2031 #endif
2032 dsn_advertised = FALSE;
2033 #ifdef SUPPORT_I18N
2034 smtputf8_advertised = FALSE;
2035 #endif
2036
2037 /* Reset ACL connection variables */
2038
2039 acl_var_c = NULL;
2040
2041 /* Allow for trailing 0 in the command and data buffers. */
2042
2043 if (!(smtp_cmd_buffer = US malloc(2*smtp_cmd_buffer_size + 2)))
2044 log_write(0, LOG_MAIN|LOG_PANIC_DIE,
2045 "malloc() failed for SMTP command buffer");
2046
2047 smtp_cmd_buffer[0] = 0;
2048 smtp_data_buffer = smtp_cmd_buffer + smtp_cmd_buffer_size + 1;
2049
2050 /* For batched input, the protocol setting can be overridden from the
2051 command line by a trusted caller. */
2052
2053 if (smtp_batched_input)
2054 {
2055 if (!received_protocol) received_protocol = US"local-bsmtp";
2056 }
2057
2058 /* For non-batched SMTP input, the protocol setting is forced here. It will be
2059 reset later if any of EHLO/AUTH/STARTTLS are received. */
2060
2061 else
2062 received_protocol =
2063 (sender_host_address ? protocols : protocols_local) [pnormal];
2064
2065 /* Set up the buffer for inputting using direct read() calls, and arrange to
2066 call the local functions instead of the standard C ones. */
2067
2068 if (!(smtp_inbuffer = (uschar *)malloc(in_buffer_size)))
2069 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "malloc() failed for SMTP input buffer");
2070
2071 receive_getc = smtp_getc;
2072 receive_get_cache = smtp_get_cache;
2073 receive_ungetc = smtp_ungetc;
2074 receive_feof = smtp_feof;
2075 receive_ferror = smtp_ferror;
2076 receive_smtp_buffered = smtp_buffered;
2077 smtp_inptr = smtp_inend = smtp_inbuffer;
2078 smtp_had_eof = smtp_had_error = 0;
2079
2080 /* Set up the message size limit; this may be host-specific */
2081
2082 thismessage_size_limit = expand_string_integer(message_size_limit, TRUE);
2083 if (expand_string_message != NULL)
2084 {
2085 if (thismessage_size_limit == -1)
2086 log_write(0, LOG_MAIN|LOG_PANIC, "unable to expand message_size_limit: "
2087 "%s", expand_string_message);
2088 else
2089 log_write(0, LOG_MAIN|LOG_PANIC, "invalid message_size_limit: "
2090 "%s", expand_string_message);
2091 smtp_closedown(US"Temporary local problem - please try later");
2092 return FALSE;
2093 }
2094
2095 /* When a message is input locally via the -bs or -bS options, sender_host_
2096 unknown is set unless -oMa was used to force an IP address, in which case it
2097 is checked like a real remote connection. When -bs is used from inetd, this
2098 flag is not set, causing the sending host to be checked. The code that deals
2099 with IP source routing (if configured) is never required for -bs or -bS and
2100 the flag sender_host_notsocket is used to suppress it.
2101
2102 If smtp_accept_max and smtp_accept_reserve are set, keep some connections in
2103 reserve for certain hosts and/or networks. */
2104
2105 if (!sender_host_unknown)
2106 {
2107 int rc;
2108 BOOL reserved_host = FALSE;
2109
2110 /* Look up IP options (source routing info) on the socket if this is not an
2111 -oMa "host", and if any are found, log them and drop the connection.
2112
2113 Linux (and others now, see below) is different to everyone else, so there
2114 has to be some conditional compilation here. Versions of Linux before 2.1.15
2115 used a structure whose name was "options". Somebody finally realized that
2116 this name was silly, and it got changed to "ip_options". I use the
2117 newer name here, but there is a fudge in the script that sets up os.h
2118 to define a macro in older Linux systems.
2119
2120 Sigh. Linux is a fast-moving target. Another generation of Linux uses
2121 glibc 2, which has chosen ip_opts for the structure name. This is now
2122 really a glibc thing rather than a Linux thing, so the condition name
2123 has been changed to reflect this. It is relevant also to GNU/Hurd.
2124
2125 Mac OS 10.x (Darwin) is like the later glibc versions, but without the
2126 setting of the __GLIBC__ macro, so we can't detect it automatically. There's
2127 a special macro defined in the os.h file.
2128
2129 Some DGUX versions on older hardware appear not to support IP options at
2130 all, so there is now a general macro which can be set to cut out this
2131 support altogether.
2132
2133 How to do this properly in IPv6 is not yet known. */
2134
2135 #if !HAVE_IPV6 && !defined(NO_IP_OPTIONS)
2136
2137 #ifdef GLIBC_IP_OPTIONS
2138 #if (!defined __GLIBC__) || (__GLIBC__ < 2)
2139 #define OPTSTYLE 1
2140 #else
2141 #define OPTSTYLE 2
2142 #endif
2143 #elif defined DARWIN_IP_OPTIONS
2144 #define OPTSTYLE 2
2145 #else
2146 #define OPTSTYLE 3
2147 #endif
2148
2149 if (!host_checking && !sender_host_notsocket)
2150 {
2151 #if OPTSTYLE == 1
2152 EXIM_SOCKLEN_T optlen = sizeof(struct ip_options) + MAX_IPOPTLEN;
2153 struct ip_options *ipopt = store_get(optlen);
2154 #elif OPTSTYLE == 2
2155 struct ip_opts ipoptblock;
2156 struct ip_opts *ipopt = &ipoptblock;
2157 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2158 #else
2159 struct ipoption ipoptblock;
2160 struct ipoption *ipopt = &ipoptblock;
2161 EXIM_SOCKLEN_T optlen = sizeof(ipoptblock);
2162 #endif
2163
2164 /* Occasional genuine failures of getsockopt() have been seen - for
2165 example, "reset by peer". Therefore, just log and give up on this
2166 call, unless the error is ENOPROTOOPT. This error is given by systems
2167 that have the interfaces but not the mechanism - e.g. GNU/Hurd at the time
2168 of writing. So for that error, carry on - we just can't do an IP options
2169 check. */
2170
2171 DEBUG(D_receive) debug_printf("checking for IP options\n");
2172
2173 if (getsockopt(fileno(smtp_out), IPPROTO_IP, IP_OPTIONS, (uschar *)(ipopt),
2174 &optlen) < 0)
2175 {
2176 if (errno != ENOPROTOOPT)
2177 {
2178 log_write(0, LOG_MAIN, "getsockopt() failed from %s: %s",
2179 host_and_ident(FALSE), strerror(errno));
2180 smtp_printf("451 SMTP service not available\r\n");
2181 return FALSE;
2182 }
2183 }
2184
2185 /* Deal with any IP options that are set. On the systems I have looked at,
2186 the value of MAX_IPOPTLEN has been 40, meaning that there should never be
2187 more logging data than will fit in big_buffer. Nevertheless, after somebody
2188 questioned this code, I've added in some paranoid checking. */
2189
2190 else if (optlen > 0)
2191 {
2192 uschar *p = big_buffer;
2193 uschar *pend = big_buffer + big_buffer_size;
2194 uschar *opt, *adptr;
2195 int optcount;
2196 struct in_addr addr;
2197
2198 #if OPTSTYLE == 1
2199 uschar *optstart = (uschar *)(ipopt->__data);
2200 #elif OPTSTYLE == 2
2201 uschar *optstart = (uschar *)(ipopt->ip_opts);
2202 #else
2203 uschar *optstart = (uschar *)(ipopt->ipopt_list);
2204 #endif
2205
2206 DEBUG(D_receive) debug_printf("IP options exist\n");
2207
2208 Ustrcpy(p, "IP options on incoming call:");
2209 p += Ustrlen(p);
2210
2211 for (opt = optstart; opt != NULL &&
2212 opt < (uschar *)(ipopt) + optlen;)
2213 {
2214 switch (*opt)
2215 {
2216 case IPOPT_EOL:
2217 opt = NULL;
2218 break;
2219
2220 case IPOPT_NOP:
2221 opt++;
2222 break;
2223
2224 case IPOPT_SSRR:
2225 case IPOPT_LSRR:
2226 if (!string_format(p, pend-p, " %s [@%s",
2227 (*opt == IPOPT_SSRR)? "SSRR" : "LSRR",
2228 #if OPTSTYLE == 1
2229 inet_ntoa(*((struct in_addr *)(&(ipopt->faddr))))))
2230 #elif OPTSTYLE == 2
2231 inet_ntoa(ipopt->ip_dst)))
2232 #else
2233 inet_ntoa(ipopt->ipopt_dst)))
2234 #endif
2235 {
2236 opt = NULL;
2237 break;
2238 }
2239
2240 p += Ustrlen(p);
2241 optcount = (opt[1] - 3) / sizeof(struct in_addr);
2242 adptr = opt + 3;
2243 while (optcount-- > 0)
2244 {
2245 memcpy(&addr, adptr, sizeof(addr));
2246 if (!string_format(p, pend - p - 1, "%s%s",
2247 (optcount == 0)? ":" : "@", inet_ntoa(addr)))
2248 {
2249 opt = NULL;
2250 break;
2251 }
2252 p += Ustrlen(p);
2253 adptr += sizeof(struct in_addr);
2254 }
2255 *p++ = ']';
2256 opt += opt[1];
2257 break;
2258
2259 default:
2260 {
2261 int i;
2262 if (pend - p < 4 + 3*opt[1]) { opt = NULL; break; }
2263 Ustrcat(p, "[ ");
2264 p += 2;
2265 for (i = 0; i < opt[1]; i++)
2266 {
2267 sprintf(CS p, "%2.2x ", opt[i]);
2268 p += 3;
2269 }
2270 *p++ = ']';
2271 }
2272 opt += opt[1];
2273 break;
2274 }
2275 }
2276
2277 *p = 0;
2278 log_write(0, LOG_MAIN, "%s", big_buffer);
2279
2280 /* Refuse any call with IP options. This is what tcpwrappers 7.5 does. */
2281
2282 log_write(0, LOG_MAIN|LOG_REJECT,
2283 "connection from %s refused (IP options)", host_and_ident(FALSE));
2284
2285 smtp_printf("554 SMTP service not available\r\n");
2286 return FALSE;
2287 }
2288
2289 /* Length of options = 0 => there are no options */
2290
2291 else DEBUG(D_receive) debug_printf("no IP options found\n");
2292 }
2293 #endif /* HAVE_IPV6 && !defined(NO_IP_OPTIONS) */
2294
2295 /* Set keep-alive in socket options. The option is on by default. This
2296 setting is an attempt to get rid of some hanging connections that stick in
2297 read() when the remote end (usually a dialup) goes away. */
2298
2299 if (smtp_accept_keepalive && !sender_host_notsocket)
2300 ip_keepalive(fileno(smtp_out), sender_host_address, FALSE);
2301
2302 /* If the current host matches host_lookup, set the name by doing a
2303 reverse lookup. On failure, sender_host_name will be NULL and
2304 host_lookup_failed will be TRUE. This may or may not be serious - optional
2305 checks later. */
2306
2307 if (verify_check_host(&host_lookup) == OK)
2308 {
2309 (void)host_name_lookup();
2310 host_build_sender_fullhost();
2311 }
2312
2313 /* Delay this until we have the full name, if it is looked up. */
2314
2315 set_process_info("handling incoming connection from %s",
2316 host_and_ident(FALSE));
2317
2318 /* Expand smtp_receive_timeout, if needed */
2319
2320 if (smtp_receive_timeout_s)
2321 {
2322 uschar * exp;
2323 if ( !(exp = expand_string(smtp_receive_timeout_s))
2324 || !(*exp)
2325 || (smtp_receive_timeout = readconf_readtime(exp, 0, FALSE)) < 0
2326 )
2327 log_write(0, LOG_MAIN|LOG_PANIC,
2328 "bad value for smtp_receive_timeout: '%s'", exp ? exp : US"");
2329 }
2330
2331 /* Start up TLS if tls_on_connect is set. This is for supporting the legacy
2332 smtps port for use with older style SSL MTAs. */
2333
2334 #ifdef SUPPORT_TLS
2335 if (tls_in.on_connect && tls_server_start(tls_require_ciphers) != OK)
2336 return FALSE;
2337 #endif
2338
2339 /* Test for explicit connection rejection */
2340
2341 if (verify_check_host(&host_reject_connection) == OK)
2342 {
2343 log_write(L_connection_reject, LOG_MAIN|LOG_REJECT, "refused connection "
2344 "from %s (host_reject_connection)", host_and_ident(FALSE));
2345 smtp_printf("554 SMTP service not available\r\n");
2346 return FALSE;
2347 }
2348
2349 /* Test with TCP Wrappers if so configured. There is a problem in that
2350 hosts_ctl() returns 0 (deny) under a number of system failure circumstances,
2351 such as disks dying. In these cases, it is desirable to reject with a 4xx
2352 error instead of a 5xx error. There isn't a "right" way to detect such
2353 problems. The following kludge is used: errno is zeroed before calling
2354 hosts_ctl(). If the result is "reject", a 5xx error is given only if the
2355 value of errno is 0 or ENOENT (which happens if /etc/hosts.{allow,deny} does
2356 not exist). */
2357
2358 #ifdef USE_TCP_WRAPPERS
2359 errno = 0;
2360 tcp_wrappers_name = expand_string(tcp_wrappers_daemon_name);
2361 if (tcp_wrappers_name == NULL)
2362 {
2363 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" "
2364 "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
2365 expand_string_message);
2366 }
2367 if (!hosts_ctl(tcp_wrappers_name,
2368 (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
2369 (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
2370 (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
2371 {
2372 if (errno == 0 || errno == ENOENT)
2373 {
2374 HDEBUG(D_receive) debug_printf("tcp wrappers rejection\n");
2375 log_write(L_connection_reject,
2376 LOG_MAIN|LOG_REJECT, "refused connection from %s "
2377 "(tcp wrappers)", host_and_ident(FALSE));
2378 smtp_printf("554 SMTP service not available\r\n");
2379 }
2380 else
2381 {
2382 int save_errno = errno;
2383 HDEBUG(D_receive) debug_printf("tcp wrappers rejected with unexpected "
2384 "errno value %d\n", save_errno);
2385 log_write(L_connection_reject,
2386 LOG_MAIN|LOG_REJECT, "temporarily refused connection from %s "
2387 "(tcp wrappers errno=%d)", host_and_ident(FALSE), save_errno);
2388 smtp_printf("451 Temporary local problem - please try later\r\n");
2389 }
2390 return FALSE;
2391 }
2392 #endif
2393
2394 /* Check for reserved slots. The value of smtp_accept_count has already been
2395 incremented to include this process. */
2396
2397 if (smtp_accept_max > 0 &&
2398 smtp_accept_count > smtp_accept_max - smtp_accept_reserve)
2399 {
2400 if ((rc = verify_check_host(&smtp_reserve_hosts)) != OK)
2401 {
2402 log_write(L_connection_reject,
2403 LOG_MAIN, "temporarily refused connection from %s: not in "
2404 "reserve list: connected=%d max=%d reserve=%d%s",
2405 host_and_ident(FALSE), smtp_accept_count - 1, smtp_accept_max,
2406 smtp_accept_reserve, (rc == DEFER)? " (lookup deferred)" : "");
2407 smtp_printf("421 %s: Too many concurrent SMTP connections; "
2408 "please try again later\r\n", smtp_active_hostname);
2409 return FALSE;
2410 }
2411 reserved_host = TRUE;
2412 }
2413
2414 /* If a load level above which only messages from reserved hosts are
2415 accepted is set, check the load. For incoming calls via the daemon, the
2416 check is done in the superior process if there are no reserved hosts, to
2417 save a fork. In all cases, the load average will already be available
2418 in a global variable at this point. */
2419
2420 if (smtp_load_reserve >= 0 &&
2421 load_average > smtp_load_reserve &&
2422 !reserved_host &&
2423 verify_check_host(&smtp_reserve_hosts) != OK)
2424 {
2425 log_write(L_connection_reject,
2426 LOG_MAIN, "temporarily refused connection from %s: not in "
2427 "reserve list and load average = %.2f", host_and_ident(FALSE),
2428 (double)load_average/1000.0);
2429 smtp_printf("421 %s: Too much load; please try again later\r\n",
2430 smtp_active_hostname);
2431 return FALSE;
2432 }
2433
2434 /* Determine whether unqualified senders or recipients are permitted
2435 for this host. Unfortunately, we have to do this every time, in order to
2436 set the flags so that they can be inspected when considering qualifying
2437 addresses in the headers. For a site that permits no qualification, this
2438 won't take long, however. */
2439
2440 allow_unqualified_sender =
2441 verify_check_host(&sender_unqualified_hosts) == OK;
2442
2443 allow_unqualified_recipient =
2444 verify_check_host(&recipient_unqualified_hosts) == OK;
2445
2446 /* Determine whether HELO/EHLO is required for this host. The requirement
2447 can be hard or soft. */
2448
2449 helo_required = verify_check_host(&helo_verify_hosts) == OK;
2450 if (!helo_required)
2451 helo_verify = verify_check_host(&helo_try_verify_hosts) == OK;
2452
2453 /* Determine whether this hosts is permitted to send syntactic junk
2454 after a HELO or EHLO command. */
2455
2456 helo_accept_junk = verify_check_host(&helo_accept_junk_hosts) == OK;
2457 }
2458
2459 /* For batch SMTP input we are now done. */
2460
2461 if (smtp_batched_input) return TRUE;
2462
2463 #ifdef SUPPORT_PROXY
2464 /* If valid Proxy Protocol source is connecting, set up session.
2465 * Failure will not allow any SMTP function other than QUIT. */
2466 proxy_session = FALSE;
2467 proxy_session_failed = FALSE;
2468 if (check_proxy_protocol_host())
2469 if (!setup_proxy_protocol_host())
2470 {
2471 proxy_session_failed = TRUE;
2472 DEBUG(D_receive)
2473 debug_printf("Failure to extract proxied host, only QUIT allowed\n");
2474 }
2475 else
2476 {
2477 sender_host_name = NULL;
2478 (void)host_name_lookup();
2479 host_build_sender_fullhost();
2480 }
2481 #endif
2482
2483 /* Run the ACL if it exists */
2484
2485 user_msg = NULL;
2486 if (acl_smtp_connect)
2487 {
2488 int rc;
2489 if ((rc = acl_check(ACL_WHERE_CONNECT, NULL, acl_smtp_connect, &user_msg,
2490 &log_msg)) != OK)
2491 {
2492 (void) smtp_handle_acl_fail(ACL_WHERE_CONNECT, rc, user_msg, log_msg);
2493 return FALSE;
2494 }
2495 }
2496
2497 /* Output the initial message for a two-way SMTP connection. It may contain
2498 newlines, which then cause a multi-line response to be given. */
2499
2500 code = US"220"; /* Default status code */
2501 esc = US""; /* Default extended status code */
2502 esclen = 0; /* Length of esc */
2503
2504 if (!user_msg)
2505 {
2506 if (!(s = expand_string(smtp_banner)))
2507 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Expansion of \"%s\" (smtp_banner) "
2508 "failed: %s", smtp_banner, expand_string_message);
2509 }
2510 else
2511 {
2512 int codelen = 3;
2513 s = user_msg;
2514 smtp_message_code(&code, &codelen, &s, NULL, TRUE);
2515 if (codelen > 4)
2516 {
2517 esc = code + 4;
2518 esclen = codelen - 4;
2519 }
2520 }
2521
2522 /* Remove any terminating newlines; might as well remove trailing space too */
2523
2524 p = s + Ustrlen(s);
2525 while (p > s && isspace(p[-1])) p--;
2526 *p = 0;
2527
2528 /* It seems that CC:Mail is braindead, and assumes that the greeting message
2529 is all contained in a single IP packet. The original code wrote out the
2530 greeting using several calls to fprint/fputc, and on busy servers this could
2531 cause it to be split over more than one packet - which caused CC:Mail to fall
2532 over when it got the second part of the greeting after sending its first
2533 command. Sigh. To try to avoid this, build the complete greeting message
2534 first, and output it in one fell swoop. This gives a better chance of it
2535 ending up as a single packet. */
2536
2537 ss = store_get(size);
2538 ptr = 0;
2539
2540 p = s;
2541 do /* At least once, in case we have an empty string */
2542 {
2543 int len;
2544 uschar *linebreak = Ustrchr(p, '\n');
2545 ss = string_catn(ss, &size, &ptr, code, 3);
2546 if (linebreak == NULL)
2547 {
2548 len = Ustrlen(p);
2549 ss = string_catn(ss, &size, &ptr, US" ", 1);
2550 }
2551 else
2552 {
2553 len = linebreak - p;
2554 ss = string_catn(ss, &size, &ptr, US"-", 1);
2555 }
2556 ss = string_catn(ss, &size, &ptr, esc, esclen);
2557 ss = string_catn(ss, &size, &ptr, p, len);
2558 ss = string_catn(ss, &size, &ptr, US"\r\n", 2);
2559 p += len;
2560 if (linebreak != NULL) p++;
2561 }
2562 while (*p != 0);
2563
2564 ss[ptr] = 0; /* string_cat leaves room for this */
2565
2566 /* Before we write the banner, check that there is no input pending, unless
2567 this synchronisation check is disabled. */
2568
2569 if (!check_sync())
2570 {
2571 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP protocol "
2572 "synchronization error (input sent without waiting for greeting): "
2573 "rejected connection from %s input=\"%s\"", host_and_ident(TRUE),
2574 string_printing(smtp_inptr));
2575 smtp_printf("554 SMTP synchronization error\r\n");
2576 return FALSE;
2577 }
2578
2579 /* Now output the banner */
2580
2581 smtp_printf("%s", ss);
2582 return TRUE;
2583 }
2584
2585
2586
2587
2588
2589 /*************************************************
2590 * Handle SMTP syntax and protocol errors *
2591 *************************************************/
2592
2593 /* Write to the log for SMTP syntax errors in incoming commands, if configured
2594 to do so. Then transmit the error response. The return value depends on the
2595 number of syntax and protocol errors in this SMTP session.
2596
2597 Arguments:
2598 type error type, given as a log flag bit
2599 code response code; <= 0 means don't send a response
2600 data data to reflect in the response (can be NULL)
2601 errmess the error message
2602
2603 Returns: -1 limit of syntax/protocol errors NOT exceeded
2604 +1 limit of syntax/protocol errors IS exceeded
2605
2606 These values fit in with the values of the "done" variable in the main
2607 processing loop in smtp_setup_msg(). */
2608
2609 static int
2610 synprot_error(int type, int code, uschar *data, uschar *errmess)
2611 {
2612 int yield = -1;
2613
2614 log_write(type, LOG_MAIN, "SMTP %s error in \"%s\" %s %s",
2615 (type == L_smtp_syntax_error)? "syntax" : "protocol",
2616 string_printing(smtp_cmd_buffer), host_and_ident(TRUE), errmess);
2617
2618 if (++synprot_error_count > smtp_max_synprot_errors)
2619 {
2620 yield = 1;
2621 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
2622 "syntax or protocol errors (last command was \"%s\")",
2623 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
2624 }
2625
2626 if (code > 0)
2627 {
2628 smtp_printf("%d%c%s%s%s\r\n", code, (yield == 1)? '-' : ' ',
2629 (data == NULL)? US"" : data, (data == NULL)? US"" : US": ", errmess);
2630 if (yield == 1)
2631 smtp_printf("%d Too many syntax or protocol errors\r\n", code);
2632 }
2633
2634 return yield;
2635 }
2636
2637
2638
2639
2640 /*************************************************
2641 * Log incomplete transactions *
2642 *************************************************/
2643
2644 /* This function is called after a transaction has been aborted by RSET, QUIT,
2645 connection drops or other errors. It logs the envelope information received
2646 so far in order to preserve address verification attempts.
2647
2648 Argument: string to indicate what aborted the transaction
2649 Returns: nothing
2650 */
2651
2652 static void
2653 incomplete_transaction_log(uschar *what)
2654 {
2655 if (sender_address == NULL || /* No transaction in progress */
2656 !LOGGING(smtp_incomplete_transaction))
2657 return;
2658
2659 /* Build list of recipients for logging */
2660
2661 if (recipients_count > 0)
2662 {
2663 int i;
2664 raw_recipients = store_get(recipients_count * sizeof(uschar *));
2665 for (i = 0; i < recipients_count; i++)
2666 raw_recipients[i] = recipients_list[i].address;
2667 raw_recipients_count = recipients_count;
2668 }
2669
2670 log_write(L_smtp_incomplete_transaction, LOG_MAIN|LOG_SENDER|LOG_RECIPIENTS,
2671 "%s incomplete transaction (%s)", host_and_ident(TRUE), what);
2672 }
2673
2674
2675
2676
2677 /*************************************************
2678 * Send SMTP response, possibly multiline *
2679 *************************************************/
2680
2681 /* There are, it seems, broken clients out there that cannot handle multiline
2682 responses. If no_multiline_responses is TRUE (it can be set from an ACL), we
2683 output nothing for non-final calls, and only the first line for anything else.
2684
2685 Arguments:
2686 code SMTP code, may involve extended status codes
2687 codelen length of smtp code; if > 4 there's an ESC
2688 final FALSE if the last line isn't the final line
2689 msg message text, possibly containing newlines
2690
2691 Returns: nothing
2692 */
2693
2694 void
2695 smtp_respond(uschar* code, int codelen, BOOL final, uschar *msg)
2696 {
2697 int esclen = 0;
2698 uschar *esc = US"";
2699
2700 if (!final && no_multiline_responses) return;
2701
2702 if (codelen > 4)
2703 {
2704 esc = code + 4;
2705 esclen = codelen - 4;
2706 }
2707
2708 /* If this is the first output for a (non-batch) RCPT command, see if all RCPTs
2709 have had the same. Note: this code is also present in smtp_printf(). It would
2710 be tidier to have it only in one place, but when it was added, it was easier to
2711 do it that way, so as not to have to mess with the code for the RCPT command,
2712 which sometimes uses smtp_printf() and sometimes smtp_respond(). */
2713
2714 if (rcpt_in_progress)
2715 {
2716 if (rcpt_smtp_response == NULL)
2717 rcpt_smtp_response = string_copy(msg);
2718 else if (rcpt_smtp_response_same &&
2719 Ustrcmp(rcpt_smtp_response, msg) != 0)
2720 rcpt_smtp_response_same = FALSE;
2721 rcpt_in_progress = FALSE;
2722 }
2723
2724 /* Not output the message, splitting it up into multiple lines if necessary. */
2725
2726 for (;;)
2727 {
2728 uschar *nl = Ustrchr(msg, '\n');
2729 if (nl == NULL)
2730 {
2731 smtp_printf("%.3s%c%.*s%s\r\n", code, final? ' ':'-', esclen, esc, msg);
2732 return;
2733 }
2734 else if (nl[1] == 0 || no_multiline_responses)
2735 {
2736 smtp_printf("%.3s%c%.*s%.*s\r\n", code, final? ' ':'-', esclen, esc,
2737 (int)(nl - msg), msg);
2738 return;
2739 }
2740 else
2741 {
2742 smtp_printf("%.3s-%.*s%.*s\r\n", code, esclen, esc, (int)(nl - msg), msg);
2743 msg = nl + 1;
2744 while (isspace(*msg)) msg++;
2745 }
2746 }
2747 }
2748
2749
2750
2751
2752 /*************************************************
2753 * Parse user SMTP message *
2754 *************************************************/
2755
2756 /* This function allows for user messages overriding the response code details
2757 by providing a suitable response code string at the start of the message
2758 user_msg. Check the message for starting with a response code and optionally an
2759 extended status code. If found, check that the first digit is valid, and if so,
2760 change the code pointer and length to use the replacement. An invalid code
2761 causes a panic log; in this case, if the log messages is the same as the user
2762 message, we must also adjust the value of the log message to show the code that
2763 is actually going to be used (the original one).
2764
2765 This function is global because it is called from receive.c as well as within
2766 this module.
2767
2768 Note that the code length returned includes the terminating whitespace
2769 character, which is always included in the regex match.
2770
2771 Arguments:
2772 code SMTP code, may involve extended status codes
2773 codelen length of smtp code; if > 4 there's an ESC
2774 msg message text
2775 log_msg optional log message, to be adjusted with the new SMTP code
2776 check_valid if true, verify the response code
2777
2778 Returns: nothing
2779 */
2780
2781 void
2782 smtp_message_code(uschar **code, int *codelen, uschar **msg, uschar **log_msg,
2783 BOOL check_valid)
2784 {
2785 int n;
2786 int ovector[3];
2787
2788 if (!msg || !*msg) return;
2789
2790 if ((n = pcre_exec(regex_smtp_code, NULL, CS *msg, Ustrlen(*msg), 0,
2791 PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int))) < 0) return;
2792
2793 if (check_valid && (*msg)[0] != (*code)[0])
2794 {
2795 log_write(0, LOG_MAIN|LOG_PANIC, "configured error code starts with "
2796 "incorrect digit (expected %c) in \"%s\"", (*code)[0], *msg);
2797 if (log_msg != NULL && *log_msg == *msg)
2798 *log_msg = string_sprintf("%s %s", *code, *log_msg + ovector[1]);
2799 }
2800 else
2801 {
2802 *code = *msg;
2803 *codelen = ovector[1]; /* Includes final space */
2804 }
2805 *msg += ovector[1]; /* Chop the code off the message */
2806 return;
2807 }
2808
2809
2810
2811
2812 /*************************************************
2813 * Handle an ACL failure *
2814 *************************************************/
2815
2816 /* This function is called when acl_check() fails. As well as calls from within
2817 this module, it is called from receive.c for an ACL after DATA. It sorts out
2818 logging the incident, and sets up the error response. A message containing
2819 newlines is turned into a multiline SMTP response, but for logging, only the
2820 first line is used.
2821
2822 There's a table of default permanent failure response codes to use in
2823 globals.c, along with the table of names. VFRY is special. Despite RFC1123 it
2824 defaults disabled in Exim. However, discussion in connection with RFC 821bis
2825 (aka RFC 2821) has concluded that the response should be 252 in the disabled
2826 state, because there are broken clients that try VRFY before RCPT. A 5xx
2827 response should be given only when the address is positively known to be
2828 undeliverable. Sigh. We return 252 if there is no VRFY ACL or it provides
2829 no explicit code, but if there is one we let it know best.
2830 Also, for ETRN, 458 is given on refusal, and for AUTH, 503.
2831
2832 From Exim 4.63, it is possible to override the response code details by
2833 providing a suitable response code string at the start of the message provided
2834 in user_msg. The code's first digit is checked for validity.
2835
2836 Arguments:
2837 where where the ACL was called from
2838 rc the failure code
2839 user_msg a message that can be included in an SMTP response
2840 log_msg a message for logging
2841
2842 Returns: 0 in most cases
2843 2 if the failure code was FAIL_DROP, in which case the
2844 SMTP connection should be dropped (this value fits with the
2845 "done" variable in smtp_setup_msg() below)
2846 */
2847
2848 int
2849 smtp_handle_acl_fail(int where, int rc, uschar *user_msg, uschar *log_msg)
2850 {
2851 BOOL drop = rc == FAIL_DROP;
2852 int codelen = 3;
2853 uschar *smtp_code;
2854 uschar *lognl;
2855 uschar *sender_info = US"";
2856 uschar *what =
2857 #ifdef WITH_CONTENT_SCAN
2858 where == ACL_WHERE_MIME ? US"during MIME ACL checks" :
2859 #endif
2860 where == ACL_WHERE_PREDATA ? US"DATA" :
2861 where == ACL_WHERE_DATA ? US"after DATA" :
2862 #ifndef DISABLE_PRDR
2863 where == ACL_WHERE_PRDR ? US"after DATA PRDR" :
2864 #endif
2865 smtp_cmd_data ?
2866 string_sprintf("%s %s", acl_wherenames[where], smtp_cmd_data) :
2867 string_sprintf("%s in \"connect\" ACL", acl_wherenames[where]);
2868
2869 if (drop) rc = FAIL;
2870
2871 /* Set the default SMTP code, and allow a user message to change it. */
2872
2873 smtp_code = rc == FAIL ? acl_wherecodes[where] : US"451";
2874 smtp_message_code(&smtp_code, &codelen, &user_msg, &log_msg,
2875 where != ACL_WHERE_VRFY);
2876
2877 /* We used to have sender_address here; however, there was a bug that was not
2878 updating sender_address after a rewrite during a verify. When this bug was
2879 fixed, sender_address at this point became the rewritten address. I'm not sure
2880 this is what should be logged, so I've changed to logging the unrewritten
2881 address to retain backward compatibility. */
2882
2883 #ifndef WITH_CONTENT_SCAN
2884 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA)
2885 #else
2886 if (where == ACL_WHERE_RCPT || where == ACL_WHERE_DATA || where == ACL_WHERE_MIME)
2887 #endif
2888 {
2889 sender_info = string_sprintf("F=<%s>%s%s%s%s ",
2890 sender_address_unrewritten ? sender_address_unrewritten : sender_address,
2891 sender_host_authenticated ? US" A=" : US"",
2892 sender_host_authenticated ? sender_host_authenticated : US"",
2893 sender_host_authenticated && authenticated_id ? US":" : US"",
2894 sender_host_authenticated && authenticated_id ? authenticated_id : US""
2895 );
2896 }
2897
2898 /* If there's been a sender verification failure with a specific message, and
2899 we have not sent a response about it yet, do so now, as a preliminary line for
2900 failures, but not defers. However, always log it for defer, and log it for fail
2901 unless the sender_verify_fail log selector has been turned off. */
2902
2903 if (sender_verified_failed != NULL &&
2904 !testflag(sender_verified_failed, af_sverify_told))
2905 {
2906 BOOL save_rcpt_in_progress = rcpt_in_progress;
2907 rcpt_in_progress = FALSE; /* So as not to treat these as the error */
2908
2909 setflag(sender_verified_failed, af_sverify_told);
2910
2911 if (rc != FAIL || LOGGING(sender_verify_fail))
2912 log_write(0, LOG_MAIN|LOG_REJECT, "%s sender verify %s for <%s>%s",
2913 host_and_ident(TRUE),
2914 ((sender_verified_failed->special_action & 255) == DEFER)? "defer":"fail",
2915 sender_verified_failed->address,
2916 (sender_verified_failed->message == NULL)? US"" :
2917 string_sprintf(": %s", sender_verified_failed->message));
2918
2919 if (rc == FAIL && sender_verified_failed->user_message != NULL)
2920 smtp_respond(smtp_code, codelen, FALSE, string_sprintf(
2921 testflag(sender_verified_failed, af_verify_pmfail)?
2922 "Postmaster verification failed while checking <%s>\n%s\n"
2923 "Several RFCs state that you are required to have a postmaster\n"
2924 "mailbox for each mail domain. This host does not accept mail\n"
2925 "from domains whose servers reject the postmaster address."
2926 :
2927 testflag(sender_verified_failed, af_verify_nsfail)?
2928 "Callback setup failed while verifying <%s>\n%s\n"
2929 "The initial connection, or a HELO or MAIL FROM:<> command was\n"
2930 "rejected. Refusing MAIL FROM:<> does not help fight spam, disregards\n"
2931 "RFC requirements, and stops you from receiving standard bounce\n"
2932 "messages. This host does not accept mail from domains whose servers\n"
2933 "refuse bounces."
2934 :
2935 "Verification failed for <%s>\n%s",
2936 sender_verified_failed->address,
2937 sender_verified_failed->user_message));
2938
2939 rcpt_in_progress = save_rcpt_in_progress;
2940 }
2941
2942 /* Sort out text for logging */
2943
2944 log_msg = log_msg ? string_sprintf(": %s", log_msg) : US"";
2945 if ((lognl = Ustrchr(log_msg, '\n'))) *lognl = 0;
2946
2947 /* Send permanent failure response to the command, but the code used isn't
2948 always a 5xx one - see comments at the start of this function. If the original
2949 rc was FAIL_DROP we drop the connection and yield 2. */
2950
2951 if (rc == FAIL)
2952 smtp_respond(smtp_code, codelen, TRUE,
2953 user_msg ? user_msg : US"Administrative prohibition");
2954
2955 /* Send temporary failure response to the command. Don't give any details,
2956 unless acl_temp_details is set. This is TRUE for a callout defer, a "defer"
2957 verb, and for a header verify when smtp_return_error_details is set.
2958
2959 This conditional logic is all somewhat of a mess because of the odd
2960 interactions between temp_details and return_error_details. One day it should
2961 be re-implemented in a tidier fashion. */
2962
2963 else
2964 if (acl_temp_details && user_msg)
2965 {
2966 if ( smtp_return_error_details
2967 && sender_verified_failed
2968 && sender_verified_failed->message
2969 )
2970 smtp_respond(smtp_code, codelen, FALSE, sender_verified_failed->message);
2971
2972 smtp_respond(smtp_code, codelen, TRUE, user_msg);
2973 }
2974 else
2975 smtp_respond(smtp_code, codelen, TRUE,
2976 US"Temporary local problem - please try later");
2977
2978 /* Log the incident to the logs that are specified by log_reject_target
2979 (default main, reject). This can be empty to suppress logging of rejections. If
2980 the connection is not forcibly to be dropped, return 0. Otherwise, log why it
2981 is closing if required and return 2. */
2982
2983 if (log_reject_target != 0)
2984 {
2985 #ifdef SUPPORT_TLS
2986 uschar * tls = s_tlslog(NULL, NULL, NULL);
2987 if (!tls) tls = US"";
2988 #else
2989 uschar * tls = US"";
2990 #endif
2991 log_write(where == ACL_WHERE_CONNECT ? L_connection_reject : 0,
2992 log_reject_target, "%s%s%s %s%srejected %s%s",
2993 LOGGING(dnssec) && sender_host_dnssec ? US" DS" : US"",
2994 host_and_ident(TRUE),
2995 tls,
2996 sender_info,
2997 rc == FAIL ? US"" : US"temporarily ",
2998 what, log_msg);
2999 }
3000
3001 if (!drop) return 0;
3002
3003 log_write(L_smtp_connection, LOG_MAIN, "%s closed by DROP in ACL",
3004 smtp_get_connection_info());
3005
3006 /* Run the not-quit ACL, but without any custom messages. This should not be a
3007 problem, because we get here only if some other ACL has issued "drop", and
3008 in that case, *its* custom messages will have been used above. */
3009
3010 smtp_notquit_exit(US"acl-drop", NULL, NULL);
3011 return 2;
3012 }
3013
3014
3015
3016
3017 /*************************************************
3018 * Handle SMTP exit when QUIT is not given *
3019 *************************************************/
3020
3021 /* This function provides a logging/statistics hook for when an SMTP connection
3022 is dropped on the floor or the other end goes away. It's a global function
3023 because it's called from receive.c as well as this module. As well as running
3024 the NOTQUIT ACL, if there is one, this function also outputs a final SMTP
3025 response, either with a custom message from the ACL, or using a default. There
3026 is one case, however, when no message is output - after "drop". In that case,
3027 the ACL that obeyed "drop" has already supplied the custom message, and NULL is
3028 passed to this function.
3029
3030 In case things go wrong while processing this function, causing an error that
3031 may re-enter this funtion, there is a recursion check.
3032
3033 Arguments:
3034 reason What $smtp_notquit_reason will be set to in the ACL;
3035 if NULL, the ACL is not run
3036 code The error code to return as part of the response
3037 defaultrespond The default message if there's no user_msg
3038
3039 Returns: Nothing
3040 */
3041
3042 void
3043 smtp_notquit_exit(uschar *reason, uschar *code, uschar *defaultrespond, ...)
3044 {
3045 int rc;
3046 uschar *user_msg = NULL;
3047 uschar *log_msg = NULL;
3048
3049 /* Check for recursive acll */
3050
3051 if (smtp_exit_function_called)
3052 {
3053 log_write(0, LOG_PANIC, "smtp_notquit_exit() called more than once (%s)",
3054 reason);
3055 return;
3056 }
3057 smtp_exit_function_called = TRUE;
3058
3059 /* Call the not-QUIT ACL, if there is one, unless no reason is given. */
3060
3061 if (acl_smtp_notquit && reason)
3062 {
3063 smtp_notquit_reason = reason;
3064 if ((rc = acl_check(ACL_WHERE_NOTQUIT, NULL, acl_smtp_notquit, &user_msg,
3065 &log_msg)) == ERROR)
3066 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for not-QUIT returned ERROR: %s",
3067 log_msg);
3068 }
3069
3070 /* Write an SMTP response if we are expected to give one. As the default
3071 responses are all internal, they should always fit in the buffer, but code a
3072 warning, just in case. Note that string_vformat() still leaves a complete
3073 string, even if it is incomplete. */
3074
3075 if (code && defaultrespond)
3076 {
3077 if (user_msg)
3078 smtp_respond(code, 3, TRUE, user_msg);
3079 else
3080 {
3081 uschar buffer[128];
3082 va_list ap;
3083 va_start(ap, defaultrespond);
3084 if (!string_vformat(buffer, sizeof(buffer), CS defaultrespond, ap))
3085 log_write(0, LOG_MAIN|LOG_PANIC, "string too large in smtp_notquit_exit()");
3086 smtp_printf("%s %s\r\n", code, buffer);
3087 va_end(ap);
3088 }
3089 mac_smtp_fflush();
3090 }
3091 }
3092
3093
3094
3095
3096 /*************************************************
3097 * Verify HELO argument *
3098 *************************************************/
3099
3100 /* This function is called if helo_verify_hosts or helo_try_verify_hosts is
3101 matched. It is also called from ACL processing if verify = helo is used and
3102 verification was not previously tried (i.e. helo_try_verify_hosts was not
3103 matched). The result of its processing is to set helo_verified and
3104 helo_verify_failed. These variables should both be FALSE for this function to
3105 be called.
3106
3107 Note that EHLO/HELO is legitimately allowed to quote an address literal. Allow
3108 for IPv6 ::ffff: literals.
3109
3110 Argument: none
3111 Returns: TRUE if testing was completed;
3112 FALSE on a temporary failure
3113 */
3114
3115 BOOL
3116 smtp_verify_helo(void)
3117 {
3118 BOOL yield = TRUE;
3119
3120 HDEBUG(D_receive) debug_printf("verifying EHLO/HELO argument \"%s\"\n",
3121 sender_helo_name);
3122
3123 if (sender_helo_name == NULL)
3124 {
3125 HDEBUG(D_receive) debug_printf("no EHLO/HELO command was issued\n");
3126 }
3127
3128 /* Deal with the case of -bs without an IP address */
3129
3130 else if (sender_host_address == NULL)
3131 {
3132 HDEBUG(D_receive) debug_printf("no client IP address: assume success\n");
3133 helo_verified = TRUE;
3134 }
3135
3136 /* Deal with the more common case when there is a sending IP address */
3137
3138 else if (sender_helo_name[0] == '[')
3139 {
3140 helo_verified = Ustrncmp(sender_helo_name+1, sender_host_address,
3141 Ustrlen(sender_host_address)) == 0;
3142
3143 #if HAVE_IPV6
3144 if (!helo_verified)
3145 {
3146 if (strncmpic(sender_host_address, US"::ffff:", 7) == 0)
3147 helo_verified = Ustrncmp(sender_helo_name + 1,
3148 sender_host_address + 7, Ustrlen(sender_host_address) - 7) == 0;
3149 }
3150 #endif
3151
3152 HDEBUG(D_receive)
3153 { if (helo_verified) debug_printf("matched host address\n"); }
3154 }
3155
3156 /* Do a reverse lookup if one hasn't already given a positive or negative
3157 response. If that fails, or the name doesn't match, try checking with a forward
3158 lookup. */
3159
3160 else
3161 {
3162 if (sender_host_name == NULL && !host_lookup_failed)
3163 yield = host_name_lookup() != DEFER;
3164
3165 /* If a host name is known, check it and all its aliases. */
3166
3167 if (sender_host_name)
3168 if ((helo_verified = strcmpic(sender_host_name, sender_helo_name) == 0))
3169 {
3170 sender_helo_dnssec = sender_host_dnssec;
3171 HDEBUG(D_receive) debug_printf("matched host name\n");
3172 }
3173 else
3174 {
3175 uschar **aliases = sender_host_aliases;
3176 while (*aliases)
3177 if ((helo_verified = strcmpic(*aliases++, sender_helo_name) == 0))
3178 {
3179 sender_helo_dnssec = sender_host_dnssec;
3180 break;
3181 }
3182
3183 HDEBUG(D_receive) if (helo_verified)
3184 debug_printf("matched alias %s\n", *(--aliases));
3185 }
3186
3187 /* Final attempt: try a forward lookup of the helo name */
3188
3189 if (!helo_verified)
3190 {
3191 int rc;
3192 host_item h;
3193 dnssec_domains d;
3194 host_item *hh;
3195
3196 h.name = sender_helo_name;
3197 h.address = NULL;
3198 h.mx = MX_NONE;
3199 h.next = NULL;
3200 d.request = US"*";
3201 d.require = US"";
3202
3203 HDEBUG(D_receive) debug_printf("getting IP address for %s\n",
3204 sender_helo_name);
3205 rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
3206 NULL, NULL, NULL, &d, NULL, NULL);
3207 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3208 for (hh = &h; hh; hh = hh->next)
3209 if (Ustrcmp(hh->address, sender_host_address) == 0)
3210 {
3211 helo_verified = TRUE;
3212 if (h.dnssec == DS_YES) sender_helo_dnssec = TRUE;
3213 HDEBUG(D_receive)
3214 {
3215 debug_printf("IP address for %s matches calling address\n"
3216 "Forward DNS security status: %sverified\n",
3217 sender_helo_name, sender_helo_dnssec ? "" : "un");
3218 }
3219 break;
3220 }
3221 }
3222 }
3223
3224 if (!helo_verified) helo_verify_failed = TRUE; /* We've tried ... */
3225 return yield;
3226 }
3227
3228
3229
3230
3231 /*************************************************
3232 * Send user response message *
3233 *************************************************/
3234
3235 /* This function is passed a default response code and a user message. It calls
3236 smtp_message_code() to check and possibly modify the response code, and then
3237 calls smtp_respond() to transmit the response. I put this into a function
3238 just to avoid a lot of repetition.
3239
3240 Arguments:
3241 code the response code
3242 user_msg the user message
3243
3244 Returns: nothing
3245 */
3246
3247 static void
3248 smtp_user_msg(uschar *code, uschar *user_msg)
3249 {
3250 int len = 3;
3251 smtp_message_code(&code, &len, &user_msg, NULL, TRUE);
3252 smtp_respond(code, len, TRUE, user_msg);
3253 }
3254
3255
3256
3257 static int
3258 smtp_in_auth(auth_instance *au, uschar ** s, uschar ** ss)
3259 {
3260 const uschar *set_id = NULL;
3261 int rc, i;
3262
3263 /* Run the checking code, passing the remainder of the command line as
3264 data. Initials the $auth<n> variables as empty. Initialize $0 empty and set
3265 it as the only set numerical variable. The authenticator may set $auth<n>
3266 and also set other numeric variables. The $auth<n> variables are preferred
3267 nowadays; the numerical variables remain for backwards compatibility.
3268
3269 Afterwards, have a go at expanding the set_id string, even if
3270 authentication failed - for bad passwords it can be useful to log the
3271 userid. On success, require set_id to expand and exist, and put it in
3272 authenticated_id. Save this in permanent store, as the working store gets
3273 reset at HELO, RSET, etc. */
3274
3275 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL;
3276 expand_nmax = 0;
3277 expand_nlength[0] = 0; /* $0 contains nothing */
3278
3279 rc = (au->info->servercode)(au, smtp_cmd_data);
3280 if (au->set_id) set_id = expand_string(au->set_id);
3281 expand_nmax = -1; /* Reset numeric variables */
3282 for (i = 0; i < AUTH_VARS; i++) auth_vars[i] = NULL; /* Reset $auth<n> */
3283
3284 /* The value of authenticated_id is stored in the spool file and printed in
3285 log lines. It must not contain binary zeros or newline characters. In
3286 normal use, it never will, but when playing around or testing, this error
3287 can (did) happen. To guard against this, ensure that the id contains only
3288 printing characters. */
3289
3290 if (set_id) set_id = string_printing(set_id);
3291
3292 /* For the non-OK cases, set up additional logging data if set_id
3293 is not empty. */
3294
3295 if (rc != OK)
3296 set_id = set_id && *set_id
3297 ? string_sprintf(" (set_id=%s)", set_id) : US"";
3298
3299 /* Switch on the result */
3300
3301 switch(rc)
3302 {
3303 case OK:
3304 if (!au->set_id || set_id) /* Complete success */
3305 {
3306 if (set_id) authenticated_id = string_copy_malloc(set_id);
3307 sender_host_authenticated = au->name;
3308 authentication_failed = FALSE;
3309 authenticated_fail_id = NULL; /* Impossible to already be set? */
3310
3311 received_protocol =
3312 (sender_host_address ? protocols : protocols_local)
3313 [pextend + pauthed + (tls_in.active >= 0 ? pcrpted:0)];
3314 *s = *ss = US"235 Authentication succeeded";
3315 authenticated_by = au;
3316 break;
3317 }
3318
3319 /* Authentication succeeded, but we failed to expand the set_id string.
3320 Treat this as a temporary error. */
3321
3322 auth_defer_msg = expand_string_message;
3323 /* Fall through */
3324
3325 case DEFER:
3326 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3327 *s = string_sprintf("435 Unable to authenticate at present%s",
3328 auth_defer_user_msg);
3329 *ss = string_sprintf("435 Unable to authenticate at present%s: %s",
3330 set_id, auth_defer_msg);
3331 break;
3332
3333 case BAD64:
3334 *s = *ss = US"501 Invalid base64 data";
3335 break;
3336
3337 case CANCELLED:
3338 *s = *ss = US"501 Authentication cancelled";
3339 break;
3340
3341 case UNEXPECTED:
3342 *s = *ss = US"553 Initial data not expected";
3343 break;
3344
3345 case FAIL:
3346 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3347 *s = US"535 Incorrect authentication data";
3348 *ss = string_sprintf("535 Incorrect authentication data%s", set_id);
3349 break;
3350
3351 default:
3352 if (set_id) authenticated_fail_id = string_copy_malloc(set_id);
3353 *s = US"435 Internal error";
3354 *ss = string_sprintf("435 Internal error%s: return %d from authentication "
3355 "check", set_id, rc);
3356 break;
3357 }
3358
3359 return rc;
3360 }
3361
3362
3363
3364
3365
3366 static int
3367 qualify_recipient(uschar ** recipient, uschar * smtp_cmd_data, uschar * tag)
3368 {
3369 int rd;
3370 if (allow_unqualified_recipient || strcmpic(*recipient, US"postmaster") == 0)
3371 {
3372 DEBUG(D_receive) debug_printf("unqualified address %s accepted\n",
3373 *recipient);
3374 rd = Ustrlen(recipient) + 1;
3375 *recipient = rewrite_address_qualify(*recipient, TRUE);
3376 return rd;
3377 }
3378 smtp_printf("501 %s: recipient address must contain a domain\r\n",
3379 smtp_cmd_data);
3380 log_write(L_smtp_syntax_error,
3381 LOG_MAIN|LOG_REJECT, "unqualified %s rejected: <%s> %s%s",
3382 tag, *recipient, host_and_ident(TRUE), host_lookup_msg);
3383 return 0;
3384 }
3385
3386
3387
3388
3389 static void
3390 smtp_quit_handler(uschar ** user_msgp, uschar ** log_msgp)
3391 {
3392 HAD(SCH_QUIT);
3393 incomplete_transaction_log(US"QUIT");
3394 if (acl_smtp_quit)
3395 {
3396 int rc = acl_check(ACL_WHERE_QUIT, NULL, acl_smtp_quit, user_msgp, log_msgp);
3397 if (rc == ERROR)
3398 log_write(0, LOG_MAIN|LOG_PANIC, "ACL for QUIT returned ERROR: %s",
3399 *log_msgp);
3400 }
3401 if (*user_msgp)
3402 smtp_respond(US"221", 3, TRUE, *user_msgp);
3403 else
3404 smtp_printf("221 %s closing connection\r\n", smtp_active_hostname);
3405
3406 #ifdef SUPPORT_TLS
3407 tls_close(TRUE, TRUE);
3408 #endif
3409
3410 log_write(L_smtp_connection, LOG_MAIN, "%s closed by QUIT",
3411 smtp_get_connection_info());
3412 }
3413
3414
3415 static void
3416 smtp_rset_handler(void)
3417 {
3418 HAD(SCH_RSET);
3419 incomplete_transaction_log(US"RSET");
3420 smtp_printf("250 Reset OK\r\n");
3421 cmd_list[CMD_LIST_RSET].is_mail_cmd = FALSE;
3422 }
3423
3424
3425
3426 /*************************************************
3427 * Initialize for SMTP incoming message *
3428 *************************************************/
3429
3430 /* This function conducts the initial dialogue at the start of an incoming SMTP
3431 message, and builds a list of recipients. However, if the incoming message
3432 is part of a batch (-bS option) a separate function is called since it would
3433 be messy having tests splattered about all over this function. This function
3434 therefore handles the case where interaction is occurring. The input and output
3435 files are set up in smtp_in and smtp_out.
3436
3437 The global recipients_list is set to point to a vector of recipient_item
3438 blocks, whose number is given by recipients_count. This is extended by the
3439 receive_add_recipient() function. The global variable sender_address is set to
3440 the sender's address. The yield is +1 if a message has been successfully
3441 started, 0 if a QUIT command was encountered or the connection was refused from
3442 the particular host, or -1 if the connection was lost.
3443
3444 Argument: none
3445
3446 Returns: > 0 message successfully started (reached DATA)
3447 = 0 QUIT read or end of file reached or call refused
3448 < 0 lost connection
3449 */
3450
3451 int
3452 smtp_setup_msg(void)
3453 {
3454 int done = 0;
3455 BOOL toomany = FALSE;
3456 BOOL discarded = FALSE;
3457 BOOL last_was_rej_mail = FALSE;
3458 BOOL last_was_rcpt = FALSE;
3459 void *reset_point = store_get(0);
3460
3461 DEBUG(D_receive) debug_printf("smtp_setup_msg entered\n");
3462
3463 /* Reset for start of new message. We allow one RSET not to be counted as a
3464 nonmail command, for those MTAs that insist on sending it between every
3465 message. Ditto for EHLO/HELO and for STARTTLS, to allow for going in and out of
3466 TLS between messages (an Exim client may do this if it has messages queued up
3467 for the host). Note: we do NOT reset AUTH at this point. */
3468
3469 smtp_reset(reset_point);
3470 message_ended = END_NOTSTARTED;
3471
3472 chunking_state = chunking_offered ? CHUNKING_OFFERED : CHUNKING_NOT_OFFERED;
3473
3474 cmd_list[CMD_LIST_RSET].is_mail_cmd = TRUE;
3475 cmd_list[CMD_LIST_HELO].is_mail_cmd = TRUE;
3476 cmd_list[CMD_LIST_EHLO].is_mail_cmd = TRUE;
3477 #ifdef SUPPORT_TLS
3478 cmd_list[CMD_LIST_STARTTLS].is_mail_cmd = TRUE;
3479 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = TRUE;
3480 #endif
3481
3482 /* Set the local signal handler for SIGTERM - it tries to end off tidily */
3483
3484 os_non_restarting_signal(SIGTERM, command_sigterm_handler);
3485
3486 /* Batched SMTP is handled in a different function. */
3487
3488 if (smtp_batched_input) return smtp_setup_batch_msg();
3489
3490 /* Deal with SMTP commands. This loop is exited by setting done to a POSITIVE
3491 value. The values are 2 larger than the required yield of the function. */
3492
3493 while (done <= 0)
3494 {
3495 const uschar **argv;
3496 uschar *etrn_command;
3497 uschar *etrn_serialize_key;
3498 uschar *errmess;
3499 uschar *log_msg, *smtp_code;
3500 uschar *user_msg = NULL;
3501 uschar *recipient = NULL;
3502 uschar *hello = NULL;
3503 uschar *s, *ss;
3504 BOOL was_rej_mail = FALSE;
3505 BOOL was_rcpt = FALSE;
3506 void (*oldsignal)(int);
3507 pid_t pid;
3508 int start, end, sender_domain, recipient_domain;
3509 int ptr, size, rc;
3510 int c;
3511 auth_instance *au;
3512 uschar *orcpt = NULL;
3513 int flags;
3514
3515 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3516 /* Check once per STARTTLS or SSL-on-connect for a TLS AUTH */
3517 if ( tls_in.active >= 0
3518 && tls_in.peercert
3519 && tls_in.certificate_verified
3520 && cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd
3521 )
3522 {
3523 cmd_list[CMD_LIST_TLS_AUTH].is_mail_cmd = FALSE;
3524 if ( acl_smtp_auth
3525 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3526 &user_msg, &log_msg)) != OK
3527 )
3528 {
3529 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3530 continue;
3531 }
3532
3533 for (au = auths; au; au = au->next)
3534 if (strcmpic(US"tls", au->driver_name) == 0)
3535 {
3536 smtp_cmd_data = NULL;
3537
3538 if (smtp_in_auth(au, &s, &ss) == OK)
3539 { DEBUG(D_auth) debug_printf("tls auth succeeded\n"); }
3540 else
3541 { DEBUG(D_auth) debug_printf("tls auth not succeeded\n"); }
3542 break;
3543 }
3544 }
3545 #endif
3546
3547 switch(smtp_read_command(TRUE))
3548 {
3549 /* The AUTH command is not permitted to occur inside a transaction, and may
3550 occur successfully only once per connection. Actually, that isn't quite
3551 true. When TLS is started, all previous information about a connection must
3552 be discarded, so a new AUTH is permitted at that time.
3553
3554 AUTH may only be used when it has been advertised. However, it seems that
3555 there are clients that send AUTH when it hasn't been advertised, some of
3556 them even doing this after HELO. And there are MTAs that accept this. Sigh.
3557 So there's a get-out that allows this to happen.
3558
3559 AUTH is initially labelled as a "nonmail command" so that one occurrence
3560 doesn't get counted. We change the label here so that multiple failing
3561 AUTHS will eventually hit the nonmail threshold. */
3562
3563 case AUTH_CMD:
3564 HAD(SCH_AUTH);
3565 authentication_failed = TRUE;
3566 cmd_list[CMD_LIST_AUTH].is_mail_cmd = FALSE;
3567
3568 if (!auth_advertised && !allow_auth_unadvertised)
3569 {
3570 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3571 US"AUTH command used when not advertised");
3572 break;
3573 }
3574 if (sender_host_authenticated)
3575 {
3576 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3577 US"already authenticated");
3578 break;
3579 }
3580 if (sender_address)
3581 {
3582 done = synprot_error(L_smtp_protocol_error, 503, NULL,
3583 US"not permitted in mail transaction");
3584 break;
3585 }
3586
3587 /* Check the ACL */
3588
3589 if ( acl_smtp_auth
3590 && (rc = acl_check(ACL_WHERE_AUTH, NULL, acl_smtp_auth,
3591 &user_msg, &log_msg)) != OK
3592 )
3593 {
3594 done = smtp_handle_acl_fail(ACL_WHERE_AUTH, rc, user_msg, log_msg);
3595 break;
3596 }
3597
3598 /* Find the name of the requested authentication mechanism. */
3599
3600 s = smtp_cmd_data;
3601 while ((c = *smtp_cmd_data) != 0 && !isspace(c))
3602 {
3603 if (!isalnum(c) && c != '-' && c != '_')
3604 {
3605 done = synprot_error(L_smtp_syntax_error, 501, NULL,
3606 US"invalid character in authentication mechanism name");
3607 goto COMMAND_LOOP;
3608 }
3609 smtp_cmd_data++;
3610 }
3611
3612 /* If not at the end of the line, we must be at white space. Terminate the
3613 name and move the pointer on to any data that may be present. */
3614
3615 if (*smtp_cmd_data != 0)
3616 {
3617 *smtp_cmd_data++ = 0;
3618 while (isspace(*smtp_cmd_data)) smtp_cmd_data++;
3619 }
3620
3621 /* Search for an authentication mechanism which is configured for use
3622 as a server and which has been advertised (unless, sigh, allow_auth_
3623 unadvertised is set). */
3624
3625 for (au = auths; au; au = au->next)
3626 if (strcmpic(s, au->public_name) == 0 && au->server &&
3627 (au->advertised || allow_auth_unadvertised))
3628 break;
3629
3630 if (au)
3631 {
3632 c = smtp_in_auth(au, &s, &ss);
3633
3634 smtp_printf("%s\r\n", s);
3635 if (c != OK)
3636 log_write(0, LOG_MAIN|LOG_REJECT, "%s authenticator failed for %s: %s",
3637 au->name, host_and_ident(FALSE), ss);
3638 }
3639 else
3640 done = synprot_error(L_smtp_protocol_error, 504, NULL,
3641 string_sprintf("%s authentication mechanism not supported", s));
3642
3643 break; /* AUTH_CMD */
3644
3645 /* The HELO/EHLO commands are permitted to appear in the middle of a
3646 session as well as at the beginning. They have the effect of a reset in
3647 addition to their other functions. Their absence at the start cannot be
3648 taken to be an error.
3649
3650 RFC 2821 says:
3651
3652 If the EHLO command is not acceptable to the SMTP server, 501, 500,
3653 or 502 failure replies MUST be returned as appropriate. The SMTP
3654 server MUST stay in the same state after transmitting these replies
3655 that it was in before the EHLO was received.
3656
3657 Therefore, we do not do the reset until after checking the command for
3658 acceptability. This change was made for Exim release 4.11. Previously
3659 it did the reset first. */
3660
3661 case HELO_CMD:
3662 HAD(SCH_HELO);
3663 hello = US"HELO";
3664 esmtp = FALSE;
3665 goto HELO_EHLO;
3666
3667 case EHLO_CMD:
3668 HAD(SCH_EHLO);
3669 hello = US"EHLO";
3670 esmtp = TRUE;
3671
3672 HELO_EHLO: /* Common code for HELO and EHLO */
3673 cmd_list[CMD_LIST_HELO].is_mail_cmd = FALSE;
3674 cmd_list[CMD_LIST_EHLO].is_mail_cmd = FALSE;
3675
3676 /* Reject the HELO if its argument was invalid or non-existent. A
3677 successful check causes the argument to be saved in malloc store. */
3678
3679 if (!check_helo(smtp_cmd_data))
3680 {
3681 smtp_printf("501 Syntactically invalid %s argument(s)\r\n", hello);
3682
3683 log_write(0, LOG_MAIN|LOG_REJECT, "rejected %s from %s: syntactically "
3684 "invalid argument(s): %s", hello, host_and_ident(FALSE),
3685 (*smtp_cmd_argument == 0)? US"(no argument given)" :
3686 string_printing(smtp_cmd_argument));
3687
3688 if (++synprot_error_count > smtp_max_synprot_errors)
3689 {
3690 log_write(0, LOG_MAIN|LOG_REJECT, "SMTP call from %s dropped: too many "
3691 "syntax or protocol errors (last command was \"%s\")",
3692 host_and_ident(FALSE), string_printing(smtp_cmd_buffer));
3693 done = 1;
3694 }
3695
3696 break;
3697 }
3698
3699 /* If sender_host_unknown is true, we have got here via the -bs interface,
3700 not called from inetd. Otherwise, we are running an IP connection and the
3701 host address will be set. If the helo name is the primary name of this
3702 host and we haven't done a reverse lookup, force one now. If helo_required
3703 is set, ensure that the HELO name matches the actual host. If helo_verify
3704 is set, do the same check, but softly. */
3705
3706 if (!sender_host_unknown)
3707 {
3708 BOOL old_helo_verified = helo_verified;
3709 uschar *p = smtp_cmd_data;
3710
3711 while (*p != 0 && !isspace(*p)) { *p = tolower(*p); p++; }
3712 *p = 0;
3713
3714 /* Force a reverse lookup if HELO quoted something in helo_lookup_domains
3715 because otherwise the log can be confusing. */
3716
3717 if (sender_host_name == NULL &&
3718 (deliver_domain = sender_helo_name, /* set $domain */
3719 match_isinlist(sender_helo_name, CUSS &helo_lookup_domains, 0,
3720 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL)) == OK)
3721 (void)host_name_lookup();
3722
3723 /* Rebuild the fullhost info to include the HELO name (and the real name
3724 if it was looked up.) */
3725
3726 host_build_sender_fullhost(); /* Rebuild */
3727 set_process_info("handling%s incoming connection from %s",
3728 (tls_in.active >= 0)? " TLS" : "", host_and_ident(FALSE));
3729
3730 /* Verify if configured. This doesn't give much security, but it does
3731 make some people happy to be able to do it. If helo_required is set,
3732 (host matches helo_verify_hosts) failure forces rejection. If helo_verify
3733 is set (host matches helo_try_verify_hosts), it does not. This is perhaps
3734 now obsolescent, since the verification can now be requested selectively
3735 at ACL time. */
3736
3737 helo_verified = helo_verify_failed = sender_helo_dnssec = FALSE;
3738 if (helo_required || helo_verify)
3739 {
3740 BOOL tempfail = !smtp_verify_helo();
3741 if (!helo_verified)
3742 {
3743 if (helo_required)
3744 {
3745 smtp_printf("%d %s argument does not match calling host\r\n",
3746 tempfail? 451 : 550, hello);
3747 log_write(0, LOG_MAIN|LOG_REJECT, "%srejected \"%s %s\" from %s",
3748 tempfail? "temporarily " : "",
3749 hello, sender_helo_name, host_and_ident(FALSE));
3750 helo_verified = old_helo_verified;
3751 break; /* End of HELO/EHLO processing */
3752 }
3753 HDEBUG(D_all) debug_printf("%s verification failed but host is in "
3754 "helo_try_verify_hosts\n", hello);
3755 }
3756 }
3757 }
3758
3759 #ifdef EXPERIMENTAL_SPF
3760 /* set up SPF context */
3761 spf_init(sender_helo_name, sender_host_address);
3762 #endif
3763
3764 /* Apply an ACL check if one is defined; afterwards, recheck
3765 synchronization in case the client started sending in a delay. */
3766
3767 if (acl_smtp_helo)
3768 if ((rc = acl_check(ACL_WHERE_HELO, NULL, acl_smtp_helo,
3769 &user_msg, &log_msg)) != OK)
3770 {
3771 done = smtp_handle_acl_fail(ACL_WHERE_HELO, rc, user_msg, log_msg);
3772 sender_helo_name = NULL;
3773 host_build_sender_fullhost(); /* Rebuild */
3774 break;
3775 }
3776 else if (!check_sync()) goto SYNC_FAILURE;
3777
3778 /* Generate an OK reply. The default string includes the ident if present,
3779 and also the IP address if present. Reflecting back the ident is intended
3780 as a deterrent to mail forgers. For maximum efficiency, and also because
3781 some broken systems expect each response to be in a single packet, arrange
3782 that the entire reply is sent in one write(). */
3783
3784 auth_advertised = FALSE;
3785 pipelining_advertised = FALSE;
3786 #ifdef SUPPORT_TLS
3787 tls_advertised = FALSE;
3788 #endif
3789 dsn_advertised = FALSE;
3790 #ifdef SUPPORT_I18N
3791 smtputf8_advertised = FALSE;
3792 #endif
3793
3794 smtp_code = US"250 "; /* Default response code plus space*/
3795 if (user_msg == NULL)
3796 {
3797 s = string_sprintf("%.3s %s Hello %s%s%s",
3798 smtp_code,
3799 smtp_active_hostname,
3800 (sender_ident == NULL)? US"" : sender_ident,
3801 (sender_ident == NULL)? US"" : US" at ",
3802 (sender_host_name == NULL)? sender_helo_name : sender_host_name);
3803
3804 ptr = Ustrlen(s);
3805 size = ptr + 1;
3806
3807 if (sender_host_address != NULL)
3808 {
3809 s = string_catn(s, &size, &ptr, US" [", 2);
3810 s = string_cat (s, &size, &ptr, sender_host_address);
3811 s = string_catn(s, &size, &ptr, US"]", 1);
3812 }
3813 }
3814
3815 /* A user-supplied EHLO greeting may not contain more than one line. Note
3816 that the code returned by smtp_message_code() includes the terminating
3817 whitespace character. */
3818
3819 else
3820 {
3821 char *ss;
3822 int codelen = 4;
3823 smtp_message_code(&smtp_code, &codelen, &user_msg, NULL, TRUE);
3824 s = string_sprintf("%.*s%s", codelen, smtp_code, user_msg);
3825 if ((ss = strpbrk(CS s, "\r\n")) != NULL)
3826 {
3827 log_write(0, LOG_MAIN|LOG_PANIC, "EHLO/HELO response must not contain "
3828 "newlines: message truncated: %s", string_printing(s));
3829 *ss = 0;
3830 }
3831 ptr = Ustrlen(s);
3832 size = ptr + 1;
3833 }
3834
3835 s = string_catn(s, &size, &ptr, US"\r\n", 2);
3836
3837 /* If we received EHLO, we must create a multiline response which includes
3838 the functions supported. */
3839
3840 if (esmtp)
3841 {
3842 s[3] = '-';
3843
3844 /* I'm not entirely happy with this, as an MTA is supposed to check
3845 that it has enough room to accept a message of maximum size before
3846 it sends this. However, there seems little point in not sending it.
3847 The actual size check happens later at MAIL FROM time. By postponing it
3848 till then, VRFY and EXPN can be used after EHLO when space is short. */
3849
3850 if (thismessage_size_limit > 0)
3851 {
3852 sprintf(CS big_buffer, "%.3s-SIZE %d\r\n", smtp_code,
3853 thismessage_size_limit);
3854 s = string_cat(s, &size, &ptr, big_buffer);
3855 }
3856 else
3857 {
3858 s = string_catn(s, &size, &ptr, smtp_code, 3);
3859 s = string_catn(s, &size, &ptr, US"-SIZE\r\n", 7);
3860 }
3861
3862 /* Exim does not do protocol conversion or data conversion. It is 8-bit
3863 clean; if it has an 8-bit character in its hand, it just sends it. It
3864 cannot therefore specify 8BITMIME and remain consistent with the RFCs.
3865 However, some users want this option simply in order to stop MUAs
3866 mangling messages that contain top-bit-set characters. It is therefore
3867 provided as an option. */
3868
3869 if (accept_8bitmime)
3870 {
3871 s = string_catn(s, &size, &ptr, smtp_code, 3);
3872 s = string_catn(s, &size, &ptr, US"-8BITMIME\r\n", 11);
3873 }
3874
3875 /* Advertise DSN support if configured to do so. */
3876 if (verify_check_host(&dsn_advertise_hosts) != FAIL)
3877 {
3878 s = string_catn(s, &size, &ptr, smtp_code, 3);
3879 s = string_catn(s, &size, &ptr, US"-DSN\r\n", 6);
3880 dsn_advertised = TRUE;
3881 }
3882
3883 /* Advertise ETRN if there's an ACL checking whether a host is
3884 permitted to issue it; a check is made when any host actually tries. */
3885
3886 if (acl_smtp_etrn != NULL)
3887 {
3888 s = string_catn(s, &size, &ptr, smtp_code, 3);
3889 s = string_catn(s, &size, &ptr, US"-ETRN\r\n", 7);
3890 }
3891
3892 /* Advertise EXPN if there's an ACL checking whether a host is
3893 permitted to issue it; a check is made when any host actually tries. */
3894
3895 if (acl_smtp_expn != NULL)
3896 {
3897 s = string_catn(s, &size, &ptr, smtp_code, 3);
3898 s = string_catn(s, &size, &ptr, US"-EXPN\r\n", 7);
3899 }
3900
3901 /* Exim is quite happy with pipelining, so let the other end know that
3902 it is safe to use it, unless advertising is disabled. */
3903
3904 if (pipelining_enable &&
3905 verify_check_host(&pipelining_advertise_hosts) == OK)
3906 {
3907 s = string_catn(s, &size, &ptr, smtp_code, 3);
3908 s = string_catn(s, &size, &ptr, US"-PIPELINING\r\n", 13);
3909 sync_cmd_limit = NON_SYNC_CMD_PIPELINING;
3910 pipelining_advertised = TRUE;
3911 }
3912
3913
3914 /* If any server authentication mechanisms are configured, advertise
3915 them if the current host is in auth_advertise_hosts. The problem with
3916 advertising always is that some clients then require users to
3917 authenticate (and aren't configurable otherwise) even though it may not
3918 be necessary (e.g. if the host is in host_accept_relay).
3919
3920 RFC 2222 states that SASL mechanism names contain only upper case
3921 letters, so output the names in upper case, though we actually recognize
3922 them in either case in the AUTH command. */
3923
3924 if ( auths
3925 #if defined(SUPPORT_TLS) && defined(AUTH_TLS)
3926 && !sender_host_authenticated
3927 #endif
3928 && verify_check_host(&auth_advertise_hosts) == OK
3929 )
3930 {
3931 auth_instance *au;
3932 BOOL first = TRUE;
3933 for (au = auths; au; au = au->next)
3934 if (au->server && (au->advertise_condition == NULL ||
3935 expand_check_condition(au->advertise_condition, au->name,
3936 US"authenticator")))
3937 {
3938 int saveptr;
3939 if (first)
3940 {
3941 s = string_catn(s, &size, &ptr, smtp_code, 3);
3942 s = string_catn(s, &size, &ptr, US"-AUTH", 5);
3943 first = FALSE;
3944 auth_advertised = TRUE;
3945 }
3946 saveptr = ptr;
3947 s = string_catn(s, &size, &ptr, US" ", 1);
3948 s = string_cat (s, &size, &ptr, au->public_name);
3949 while (++saveptr < ptr) s[saveptr] = toupper(s[saveptr]);
3950 au->advertised = TRUE;
3951 }
3952 else
3953 au->advertised = FALSE;
3954
3955 if (!first) s = string_catn(s, &size, &ptr, US"\r\n", 2);
3956 }
3957
3958 /* RFC 3030 CHUNKING */
3959
3960 if (verify_check_host(&chunking_advertise_hosts) != FAIL)
3961 {
3962 s = string_catn(s, &size, &ptr, smtp_code, 3);
3963 s = string_catn(s, &size, &ptr, US"-CHUNKING\r\n", 11);
3964 chunking_offered = TRUE;
3965 chunking_state = CHUNKING_OFFERED;
3966 }
3967
3968 /* Advertise TLS (Transport Level Security) aka SSL (Secure Socket Layer)
3969 if it has been included in the binary, and the host matches
3970 tls_advertise_hosts. We must *not* advertise if we are already in a
3971 secure connection. */
3972
3973 #ifdef SUPPORT_TLS
3974 if (tls_in.active < 0 &&
3975 verify_check_host(&tls_advertise_hosts) != FAIL)
3976 {
3977 s = string_catn(s, &size, &ptr, smtp_code, 3);
3978 s = string_catn(s, &size, &ptr, US"-STARTTLS\r\n", 11);
3979 tls_advertised = TRUE;
3980 }
3981 #endif
3982
3983 #ifndef DISABLE_PRDR
3984 /* Per Recipient Data Response, draft by Eric A. Hall extending RFC */
3985 if (prdr_enable)
3986 {
3987 s = string_catn(s, &size, &ptr, smtp_code, 3);
3988 s = string_catn(s, &size, &ptr, US"-PRDR\r\n", 7);
3989 }
3990 #endif
3991
3992 #ifdef SUPPORT_I18N
3993 if ( accept_8bitmime
3994 && verify_check_host(&smtputf8_advertise_hosts) != FAIL)
3995 {
3996 s = string_catn(s, &size, &ptr, smtp_code, 3);
3997 s = string_catn(s, &size, &ptr, US"-SMTPUTF8\r\n", 11);
3998 smtputf8_advertised = TRUE;
3999 }
4000 #endif
4001
4002 /* Finish off the multiline reply with one that is always available. */
4003
4004 s = string_catn(s, &size, &ptr, smtp_code, 3);
4005 s = string_catn(s, &size, &ptr, US" HELP\r\n", 7);
4006 }
4007
4008 /* Terminate the string (for debug), write it, and note that HELO/EHLO
4009 has been seen. */
4010
4011 s[ptr] = 0;
4012
4013 #ifdef SUPPORT_TLS
4014 if (tls_in.active >= 0) (void)tls_write(TRUE, s, ptr); else
4015 #endif
4016
4017 {
4018 int i = fwrite(s, 1, ptr, smtp_out); i = i; /* compiler quietening */
4019 }
4020 DEBUG(D_receive)
4021 {
4022 uschar *cr;
4023 while ((cr = Ustrchr(s, '\r')) != NULL) /* lose CRs */
4024 memmove(cr, cr + 1, (ptr--) - (cr - s));
4025 debug_printf("SMTP>> %s", s);
4026 }
4027 helo_seen = TRUE;
4028
4029 /* Reset the protocol and the state, abandoning any previous message. */
4030 received_protocol =
4031 (sender_host_address ? protocols : protocols_local)
4032 [ (esmtp
4033 ? pextend + (sender_host_authenticated ? pauthed : 0)
4034 : pnormal)
4035 + (tls_in.active >= 0 ? pcrpted : 0)
4036 ];
4037 smtp_reset(reset_point);
4038 toomany = FALSE;
4039 break; /* HELO/EHLO */
4040
4041
4042 /* The MAIL command requires an address as an operand. All we do
4043 here is to parse it for syntactic correctness. The form "<>" is
4044 a special case which converts into an empty string. The start/end
4045 pointers in the original are not used further for this address, as
4046 it is the canonical extracted address which is all that is kept. */
4047
4048 case MAIL_CMD:
4049 HAD(SCH_MAIL);
4050 smtp_mailcmd_count++; /* Count for limit and ratelimit */
4051 was_rej_mail = TRUE; /* Reset if accepted */
4052 env_mail_type_t * mail_args; /* Sanity check & validate args */
4053
4054 if (helo_required && !helo_seen)
4055 {
4056 smtp_printf("503 HELO or EHLO required\r\n");
4057 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL from %s: no "
4058 "HELO/EHLO given", host_and_ident(FALSE));
4059 break;
4060 }
4061
4062 if (sender_address != NULL)
4063 {
4064 done = synprot_error(L_smtp_protocol_error, 503, NULL,
4065 US"sender already given");
4066 break;
4067 }
4068
4069 if (smtp_cmd_data[0] == 0)
4070 {
4071 done = synprot_error(L_smtp_protocol_error, 501, NULL,
4072 US"MAIL must have an address operand");
4073 break;
4074 }
4075
4076 /* Check to see if the limit for messages per connection would be
4077 exceeded by accepting further messages. */
4078
4079 if (smtp_accept_max_per_connection > 0 &&
4080 smtp_mailcmd_count > smtp_accept_max_per_connection)
4081 {
4082 smtp_printf("421 too many messages in this connection\r\n");
4083 log_write(0, LOG_MAIN|LOG_REJECT, "rejected MAIL command %s: too many "
4084 "messages in one connection", host_and_ident(TRUE));
4085 break;
4086 }
4087
4088 /* Reset for start of message - even if this is going to fail, we
4089 obviously need to throw away any previous data. */
4090
4091 smtp_reset(reset_point);
4092 toomany = FALSE;